-%%
-%%
-
\chapter{Testing Your Tape Drive With Bacula}
\label{TapeTestingChapter}
\index[general]{Testing Your Tape Drive With Bacula}
This chapter is concerned with testing and configuring your tape drive to make
-sure that it will work properly with Bacula using the {\bf btape} program.
+sure that it will work properly with Bacula using the {\bf btape} program.
\label{summary}
\section{Get Your Tape Drive Working}
In general, you should follow the following steps to get your tape drive to
work with Bacula. Start with a tape mounted in your drive. If you have an
autochanger, load a tape into the drive. We use {\bf /dev/nst0} as the tape
-drive name, you will need to adapt it according to your system.
+drive name, you will need to adapt it according to your system.
Do not proceed to the next item until you have succeeded with the previous
-one.
+one.
\begin{enumerate}
\item Make sure that Bacula (the Storage daemon) is not running
- or that you have {\bf unmount}ed the drive you will use
+ or that you have {\bf unmount}ed the drive you will use
for testing.
-\item Use tar to write to, then read from your drive:
+\item Use tar to write to, then read from your drive:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
mt -f /dev/nst0 rewind
tar cvf /dev/nst0 .
mt -f /dev/nst0 rewind
tar tvf /dev/nst0
-
-\end{verbatim}
+
+\end{lstlisting}
\normalsize
\item Make sure you have a valid and correct Device resource corresponding
to your drive. For Linux users, generally, the default one works. For
FreeBSD users, there are two possible Device configurations (see below).
For other drives and/or OSes, you will need to first ensure that your
- system tape modes are properly setup (see below), then possibly modify
+ system tape modes are properly setup (see below), then possibly modify
you Device resource depending on the output from the btape program (next
- item). When doing this, you should consult the \ilink{Storage Daemon
- Configuration}{StoredConfChapter} of this manual.
+ item). When doing this, you should consult the \bsysxrlink{Storage Daemon
+ Configuration}{StoredConfChapter}{main}{chapter} of the \mainman{}.
\item If you are using a Fibre Channel to connect your tape drive to
Bacula, please be sure to disable any caching in the NSR (network
storage router, which is a Fibre Channel to SCSI converter).
-\item Run the btape {\bf test} command:
+\item Run the btape {\bf test} command:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
./btape -c bacula-sd.conf /dev/nst0
test
-
-\end{verbatim}
+
+\end{lstlisting}
\normalsize
It isn't necessary to run the autochanger part of the test at this time,
but do not go past this point until the basic test succeeds. If you do
- have an autochanger, please be sure to read the \ilink{Autochanger
- chapter}{AutochangersChapter} of this manual.
+ have an autochanger, please be sure to read the \bsysxrlink{Autochanger
+ chapter}{AutochangersChapter}{main}{chapter} of the \mainman{}.
\item Run the btape {\bf fill} command, preferably with two volumes. This
can take a long time. If you have an autochanger and it is configured, Bacula
will automatically use it. If you do not have it configured, you can manually
issue the appropriate {\bf mtx} command, or press the autochanger buttons to
- change the tape when requested to do so.
+ change the tape when requested to do so.
\item FreeBSD users, if you have a pre-5.0 system run the {\bf tapetest}
program, and make sure your system is patched if necessary. The tapetest
directory. Then stop and restart Bacula.
\item Do a restore of the directory backed up, by entering the following
- restore command, being careful to restore it to an alternate location:
+ restore command, being careful to restore it to an alternate location:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
restore select all done
yes
-
-\end{verbatim}
+
+\end{lstlisting}
\normalsize
Do a {\bf diff} on the restored directory to ensure it is identical to the
on each system type.
\item If you have an autochanger, you should now go back to the btape program
- and run the autochanger test:
+ and run the autochanger test:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
./btape -c bacula-sd.conf /dev/nst0
auto
-
-\end{verbatim}
+
+\end{lstlisting}
\normalsize
Adjust your autochanger as necessary to ensure that it works correctly. See
the Autochanger chapter of this manual for a complete discussion of testing
- your autochanger.
+ your autochanger.
\item We strongly recommend that you use a dedicated SCSI
controller for your tape drives. Scanners are known to induce
the following was most likely caused by a scanner:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
Feb 14 17:29:55 epohost kernel: (scsi0:A:2:0): No or incomplete CDB sent to device.
Feb 14 17:29:55 epohost kernel: scsi0: Issued Channel A Bus Reset. 1 SCBs aborted
-\end{verbatim}
+\end{lstlisting}
\normalsize
\end{enumerate}
work. If you get into trouble at any point, {\bf carefully} read the
documentation given below. If you cannot get past some point, ask the {\bf
bacula-users} email list, but specify which of the steps you have successfully
-completed. In particular, you may want to look at the
-\ilink{ Tips for Resolving Problems}{problems1} section below.
+completed. In particular, you may want to look at the
+\ilink{Tips for Resolving Problems}{problems1} section below.
\label{NoTapeInDrive}
Without those parameters, the testing and utility programs do not know how to
properly read and write your drive. By default, they use {\bf bacula-sd.conf}
in the current directory, but you may specify a different configuration file
-using the {\bf -c} option.
+using the {\bf -c} option.
\subsection{Specifying a Device Name For a Tape}
\index[general]{Tape!Specifying a Device Name For a}
directive. For the program to work, it must find the identical name in the
Device resource of the configuration file. If the name is not found in the
list of physical names, the utility program will compare the name you entered
-to the Device names (rather than the Archive device names).
+to the Device names (rather than the Archive device names).
When specifying a tape device, it is preferable that the "non-rewind"
variant of the device file name be given. In addition, on systems such as
what is needed in this case. Bacula does not support SysV tape drive
behavior.
-See below for specifying Volume names.
+See below for specifying Volume names.
\subsection{Specifying a Device Name For a File}
\index[general]{File!Specifying a Device Name For a}
interface. The {\bf test} command, described below, can be very useful for
testing tape drive compatibility problems. Aside from initial testing of tape
drive compatibility with {\bf Bacula}, {\bf btape} will be mostly used by
-developers writing new tape drivers.
+developers writing new tape drivers.
{\bf btape} can be dangerous to use with existing {\bf Bacula} tapes because
it will relabel a tape or write on the tape if so requested regardless of
whether or not the tape contains valuable data, so please be careful and use
-it only on blank tapes.
+it only on blank tapes.
To work properly, {\bf btape} needs to read the Storage daemon's configuration
file. As a default, it will look for {\bf bacula-sd.conf} in the current
directory. If your configuration file is elsewhere, please use the {\bf -c}
-option to specify where.
+option to specify where.
The physical device name or the Device resource name must be specified on the
command line, and this same device name must be present in the Storage
-daemon's configuration file read by {\bf btape}
+daemon's configuration file read by {\bf btape}
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
Usage: btape [options] device_name
-b <file> specify bootstrap file
-c <file> set configuration file to file
-s turn off signals
-v be verbose
-? print this message.
-\end{verbatim}
+\end{lstlisting}
\normalsize
\subsection{Using btape to Verify your Tape Drive}
An important reason for this program is to ensure that a Storage daemon
configuration file is defined so that Bacula will correctly read and write
-tapes.
+tapes.
It is highly recommended that you run the {\bf test} command before running
your first Bacula job to ensure that the parameters you have defined for your
storage device (tape drive) will permit {\bf Bacula} to function properly. You
only need to mount a blank tape, enter the command, and the output should be
-reasonably self explanatory. For example:
+reasonably self explanatory. For example:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
(ensure that Bacula is not running)
./btape -c /usr/bin/bacula/bacula-sd.conf /dev/nst0
-\end{verbatim}
+\end{lstlisting}
\normalsize
-The output will be:
+The output will be:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
Tape block granularity is 1024 bytes.
btape: btape.c:376 Using device: /dev/nst0
*
-\end{verbatim}
+\end{lstlisting}
\normalsize
-Enter the test command:
+Enter the test command:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
test
-\end{verbatim}
+\end{lstlisting}
\normalsize
The output produced should be something similar to the following: I've cut the
-listing short because it is frequently updated to have new tests.
+listing short because it is frequently updated to have new tests.
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
=== Append files test ===
This test is essential to Bacula.
I'm going to write one record in file 0,
Now the important part, I am going to attempt to append to the tape.
...
=== End Append files test ===
-\end{verbatim}
+\end{lstlisting}
\normalsize
If you do not successfully complete the above test, please resolve the
problem(s) before attempting to use {\bf Bacula}. Depending on your tape
drive, the test may recommend that you add certain records to your
configuration. We strongly recommend that you do so and then re-run the above
-test to insure it works the first time.
+test to insure it works the first time.
Some of the suggestions it provides for resolving the problems may or may not
be useful. If at all possible avoid using fixed blocking. If the test suddenly
-starts to print a long series of:
+starts to print a long series of:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
Got EOF on tape.
Got EOF on tape.
...
-\end{verbatim}
+\end{lstlisting}
\normalsize
then almost certainly, you are running your drive in fixed block mode rather
See the section above on setting your {\bf Archive device} correctly.
For FreeBSD users, please see the notes below for doing further testing of
-your tape drive.
+your tape drive.
+
+\subsection{Testing tape drive speed}
+\label{sec:btapespeed}
+
+To determine the best configuration of your tape drive, you can run the
+\texttt{speed} command available in the \texttt{btape} program.
+
+This command can have the following arguments:
+\begin{itemize}
+\item[\texttt{file\_size=n}] Specify the Maximum File Size for this test
+ (between 1 and 5GB). This counter is in GB.
+\item[\texttt{nb\_file=n}] Specify the number of file to be written. The amount
+ of data should be greater than your memory ($file\_size*nb\_file$).
+\item[\texttt{skip\_zero}] This flag permits to skip tests with constant
+ data.
+\item[\texttt{skip\_random}] This flag permits to skip tests with random
+ data.
+\item[\texttt{skip\_raw}] This flag permits to skip tests with raw access.
+\item[\texttt{skip\_block}] This flag permits to skip tests with Bacula block
+ access.
+\end{itemize}
+
+\begin{lstlisting}
+*speed file_size=3 skip_raw
+btape.c:1078 Test with zero data and bacula block structure.
+btape.c:956 Begin writing 3 files of 3.221 GB with blocks of 129024 bytes.
+++++++++++++++++++++++++++++++++++++++++++
+btape.c:604 Wrote 1 EOF to "Drive-0" (/dev/nst0)
+btape.c:406 Volume bytes=3.221 GB. Write rate = 44.128 MB/s
+...
+btape.c:383 Total Volume bytes=9.664 GB. Total Write rate = 43.531 MB/s
+
+btape.c:1090 Test with random data, should give the minimum throughput.
+btape.c:956 Begin writing 3 files of 3.221 GB with blocks of 129024 bytes.
++++++++++++++++++++++++++++++++++++++++++++
+btape.c:604 Wrote 1 EOF to "Drive-0" (/dev/nst0)
+btape.c:406 Volume bytes=3.221 GB. Write rate = 7.271 MB/s
++++++++++++++++++++++++++++++++++++++++++++
+...
+btape.c:383 Total Volume bytes=9.664 GB. Total Write rate = 7.365 MB/s
+
+\end{lstlisting}
+
+When using compression, the random test will give your the minimum throughput
+of your drive . The test using constant string will give you the maximum speed
+of your hardware chain. (cpu, memory, scsi card, cable, drive, tape).
+
+You can change the block size in the Storage Daemon configuration file.
\label{SCSITricks}
\subsection{Linux SCSI Tricks}
\index[general]{Tricks!Linux SCSI}
\index[general]{Linux SCSI Tricks}
-You can find out what SCSI devices you have by doing:
+You can find out what SCSI devices you have by doing:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
lsscsi
-\end{verbatim}
+\end{lstlisting}
\normalsize
Typical output is:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
[0:0:0:0] disk ATA ST3160812AS 3.AD /dev/sda
[2:0:4:0] tape HP Ultrium 2-SCSI F6CH /dev/st0
[2:0:5:0] tape HP Ultrium 2-SCSI F6CH /dev/st1
[2:0:6:0] mediumx OVERLAND LXB 0107 -
[2:0:9:0] tape HP Ultrium 1-SCSI E50H /dev/st2
[2:0:10:0] mediumx OVERLAND LXB 0107 -
-\end{verbatim}
+\end{lstlisting}
\normalsize
There are two drives in one autochanger: /dev/st0 and /dev/st1
information as follows:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
cat /proc/scsi/scsi
-\end{verbatim}
+\end{lstlisting}
\normalsize
For the above example with the three drives and two autochangers,
I get:
-\footnotesize
-\begin{verbatim}
+\footnotesize
+\begin{lstlisting}
Attached devices:
Host: scsi0 Channel: 00 Id: 00 Lun: 00
Vendor: ATA Model: ST3160812AS Rev: 3.AD
Host: scsi2 Channel: 00 Id: 10 Lun: 00
Vendor: OVERLAND Model: LXB Rev: 0107
Type: Medium Changer ANSI SCSI revision: 02
-\end{verbatim}
+\end{lstlisting}
\normalsize
above example):
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
Attached devices:
Host: scsi2 Channel: 00 Id: 01 Lun: 00
Vendor: HP Model: C5713A Rev: H107
Host: scsi2 Channel: 00 Id: 04 Lun: 00
Vendor: SONY Model: SDT-10000 Rev: 0110
Type: Sequential-Access ANSI SCSI revision: 02
-\end{verbatim}
+\end{lstlisting}
\normalsize
The above represents first an autochanger and second a simple
tape drive. The HP changer (the first entry) uses the same SCSI channel
-for data and for control, so in Bacula, you would use:
+for data and for control, so in Bacula, you would use:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
Archive Device = /dev/nst0
Changer Device = /dev/sg0
-\end{verbatim}
+\end{lstlisting}
\normalsize
-If you want to remove the SDT-10000 device, you can do so as root with:
+If you want to remove the SDT-10000 device, you can do so as root with:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
echo "scsi remove-single-device 2 0 4 0">/proc/scsi/scsi
-\end{verbatim}
+\end{lstlisting}
\normalsize
-and you can put add it back with:
+and you can put add it back with:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
echo "scsi add-single-device 2 0 4 0">/proc/scsi/scsi
-\end{verbatim}
+\end{lstlisting}
\normalsize
where the 2 0 4 0 are the Host, Channel, Id, and Lun as seen on the output
from {\bf cat /proc/scsi/scsi}. Note, the Channel must be specified as
-numeric.
+numeric.
Below is a slightly more complicated output, which is a single autochanger
with two drives, and which operates the changer on a different channel
from from the drives:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
Attached devices:
Host: scsi0 Channel: 00 Id: 00 Lun: 00
Vendor: ATA Model: WDC WD1600JD-75H Rev: 08.0
Host: scsi2 Channel: 00 Id: 06 Lun: 00
Vendor: OVERLAND Model: LXB Rev: 0106
Type: Medium Changer ANSI SCSI revision: 02
-\end{verbatim}
+\end{lstlisting}
\normalsize
The above tape drives are accessed on /dev/nst0 and /dev/nst1, while
\index[general]{Files!Bacula Saves But Cannot Restore}
\index[general]{Bacula Saves But Cannot Restore Files}
-If you are getting error messages such as:
+If you are getting error messages such as:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
Volume data error at 0:1! Wanted block-id: "BB02", got "". Buffer discarded
-\end{verbatim}
+\end{lstlisting}
\normalsize
It is very likely that Bacula has tried to do block positioning and ended up
at an invalid block. This can happen if your tape drive is in fixed block mode
while Bacula's default is variable blocks. Note that in such cases, Bacula is
perfectly able to write to your Volumes (tapes), but cannot position to read
-them.
+them.
-There are two possible solutions.
+There are two possible solutions.
\begin{enumerate}
\item The first and best is to always ensure that your drive is in variable
block mode. Note, it can switch back to fixed block mode on a reboot or if
another program uses the drive. So on such systems you need to modify the
- Bacula startup files to explicitly set:
+ Bacula startup files to explicitly set:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
mt -f /dev/nst0 defblksize 0
-\end{verbatim}
+\end{lstlisting}
\normalsize
or whatever is appropriate on your system. Note, if you are running a Linux
\item The second possibility, especially, if Bacula wrote while the drive was
in fixed block mode, is to turn off block positioning in Bacula. This is done
- by adding:
+ by adding:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
Block Positioning = no
-\end{verbatim}
+\end{lstlisting}
\normalsize
to the Device resource. This is not the recommended procedure because it can
-enormously slow down recovery of files, but it may help where all else
+enormously slow down recovery of files, but it may help where all else
fails. This directive is available in version 1.35.5 or later (and not yet
-tested).
+tested).
\end{enumerate}
If you are getting error messages such as:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
Volume data error at 0:0!
Block checksum mismatch in block=0 len=32625 calc=345678 blk=123456
-\end{verbatim}
+\end{lstlisting}
\normalsize
-You are getting tape read errors, and this is most likely due to
+You are getting tape read errors, and this is most likely due to
one of the following things:
\begin{enumerate}
\item An old or bad tape.
\index[general]{Device!Bacula Cannot Open the}
\index[general]{Bacula Cannot Open the Device}
-If you get an error message such as:
+If you get an error message such as:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
dev open failed: dev.c:265 stored: unable to open
device /dev/nst0:> ERR=No such device or address
-\end{verbatim}
+\end{lstlisting}
\normalsize
the first time you run a job, it is most likely due to the fact that you
-specified the incorrect device name on your {\bf Archive Device}.
+specified the incorrect device name on your {\bf Archive Device}.
If Bacula works fine with your drive, then all off a sudden you get error
messages similar to the one shown above, it is quite possible that your driver
{\bf crontab} with the use of {\bf rmmod -a}. To fix the problem, you can
remove this entry from {\bf crontab}, or you can manually {\bf modprob} your
driver module (or add it to the local startup script). Thanks to Alan Brown
-for this tip.
+for this tip.
\label{IncorrectFiles}
\subsection{Incorrect File Number}
doing so, they will not know the current file position and hence return a {\bf
-1}. As a consequence, if you get {\bf "This is NOT correct!"} in the
positioning tests, this may be the cause. You must correct this condition in
-order for Bacula to work.
+order for Bacula to work.
There are two possible solutions to the above problem of incorrect file
-number:
+number:
\begin{itemize}
\item Figure out how to configure your SCSI driver to keep track of the file
- position during the MTEOM request. This is the preferred solution.
+ position during the MTEOM request. This is the preferred solution.
\item Modify the {\bf Device} resource of your {\bf bacula-sd.conf} file to
- include:
+ include:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
Hardware End of File = no
-\end{verbatim}
+\end{lstlisting}
\normalsize
This will cause Bacula to use the MTFSF request to seek to the end of the
-medium, and Bacula will keep track of the file number itself.
+medium, and Bacula will keep track of the file number itself.
\end{itemize}
\label{IncorrectBlocks}
{\bf Bacula's} preferred method of working with tape drives (sequential
devices) is to run in variable block mode, and this is what is set by default.
You should first ensure that your tape drive is set for variable block mode
-(see below).
+(see below).
If your tape drive is in fixed block mode and you have told Bacula to use
different fixed block sizes or variable block sizes (default), you will get
errors when Bacula attempts to forward space to the correct block (the kernel
-driver's idea of tape blocks will not correspond to Bacula's).
+driver's idea of tape blocks will not correspond to Bacula's).
All modern tape drives support variable tape blocks, but some older drives (in
particular the QIC drives) as well as the ATAPI ide-scsi driver run only in
fixed block mode. The Travan tape drives also apparently must run in fixed
-block mode (to be confirmed).
+block mode (to be confirmed).
Even in variable block mode, with the exception of the first record on the
second or subsequent volume of a multi-volume backup, Bacula will write blocks
of a fixed size. However, in reading a tape, Bacula will assume that for each
read request, exactly one block from the tape will be transferred. This the
-most common way that tape drives work and is well supported by {\bf Bacula}.
+most common way that tape drives work and is well supported by {\bf Bacula}.
Drives that run in fixed block mode can cause serious problems for Bacula if
the drive's block size does not correspond exactly to {\bf Bacula's} block
block mode, and almost all modern drives (the OnStream is an exception) run in
variable block mode. In order for Bacula to run in fixed block mode, you must
include the following records in the Storage daemon's Device resource
-definition:
+definition:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
Minimum Block Size = nnn
Maximum Block Size = nnn
-\end{verbatim}
+\end{lstlisting}
\normalsize
where {\bf nnn} must be the same for both records and must be identical to the
-driver's fixed block size.
+driver's fixed block size.
We recommend that you avoid this configuration if at all possible by using
-variable block sizes.
+variable block sizes.
If you must run with fixed size blocks, make sure they are not 512 bytes. This
is too small and the overhead that Bacula has with each record will become
excessive. If at all possible set any fixed block size to something like
64,512 bytes or possibly 32,768 if 64,512 is too large for your drive. See
-below for the details on checking and setting the default drive block size.
+below for the details on checking and setting the default drive block size.
-To recover files from tapes written in fixed block mode, see below.
+To recover files from tapes written in fixed block mode, see below.
\label{TapeModes}
\subsection{Ensuring that the Tape Modes Are Properly Set -- {\bf Linux
driver is set to work in SysV manner, Bacula will not work correctly because
it expects BSD behavior. To reset your tape drive to the default values, you
can try the following, but {\bf ONLY} if you have a SCSI tape drive on a {\bf
-Linux} system:
+Linux} system:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
become super user
mt -f /dev/nst0 rewind
mt -f /dev/nst0 stoptions buffer-writes async-writes read-ahead
-\end{verbatim}
+\end{lstlisting}
\normalsize
The above commands will clear all options and then set those specified. None
behavior. On systems other than Linux, you will need to consult your {\bf mt}
man pages or documentation to figure out how to do the same thing. This should
not really be necessary though -- for example, on both Linux and Solaris
-systems, the default tape driver options are compatible with Bacula.
+systems, the default tape driver options are compatible with Bacula.
On Solaris systems, you must take care to specify the correct device
name on the {\bf Archive device} directive. See above for more details.
You may also want to ensure that no prior program has set the default block
-size, as happened to one user, by explicitly turning it off with:
+size, as happened to one user, by explicitly turning it off with:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
mt -f /dev/nst0 defblksize 0
-\end{verbatim}
+\end{lstlisting}
\normalsize
If you are running a Linux
If you would like to know what options you have set before making any of the
changes noted above, you can now view them on Linux systems, thanks to a tip
-provided by Willem Riede. Do the following:
+provided by Willem Riede. Do the following:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
become super user
mt -f /dev/nst0 stsetoptions 0
grep st0 /var/log/messages
-\end{verbatim}
+\end{lstlisting}
\normalsize
-and you will get output that looks something like the following:
+and you will get output that looks something like the following:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
kernel: st0: Mode 0 options: buffer writes: 1, async writes: 1, read ahead: 1
kernel: st0: can bsr: 0, two FMs: 0, fast mteom: 0, auto lock: 0,
kernel: st0: defs for wr: 0, no block limits: 0, partitions: 0, s2 log: 0
kernel: st0: sysv: 0 nowait: 0
-\end{verbatim}
+\end{lstlisting}
\normalsize
Note, I have chopped off the beginning of the line with the date and machine
-name for presentation purposes.
+name for presentation purposes.
Some people find that the above settings only last until the next reboot, so
-please check this otherwise you may have unexpected problems.
+please check this otherwise you may have unexpected problems.
Beginning with Bacula version 1.35.8, if Bacula detects that you are running
in variable block mode, it will attempt to set your drive appropriately. All
OSes permit setting variable block mode, but some OSes do not permit setting
-the other modes that Bacula needs to function properly.
+the other modes that Bacula needs to function properly.
\label{compression}
\subsection{Tape Hardware Compression and Blocking Size}
\index[general]{Size!Tape Hardware Compression and Blocking Size}
You should be able to verify the tape compression status with sysfs on Linux.
-\begin{verbatim}
+\begin{lstlisting}
cat /sys/class/scsi_tape/nst0/default_compression
-\end{verbatim}
+\end{lstlisting}
-You can, turn it on by using (on Linux):
+You can, turn it on by using (on Linux):
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
become super user
mt -f /dev/nst0 defcompression 1
-\end{verbatim}
+\end{lstlisting}
\normalsize
and of course, if you use a zero instead of the one at the end, you will turn
-it off.
+it off.
If you have built the {\bf mtx} program in the {\bf depkgs} package, you can
use tapeinfo to get quite a bit of information about your tape drive even if
it is not an autochanger. This program is called using the SCSI control
device. On Linux for tape drive /dev/nst0, this is usually /dev/sg0, while on
FreeBSD for /dev/nsa0, the control device is often /dev/pass2. For example on
-my DDS-4 drive (/dev/nst0), I get the following:
+my DDS-4 drive (/dev/nst0), I get the following:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
tapeinfo -f /dev/sg0
Product Type: Tape Drive
Vendor ID: 'HP '
BufferedMode: yes
Medium Type: Not Loaded
Density Code: 0x26
-BlockSize: 0
-\end{verbatim}
+BlockSize: 0
+\end{lstlisting}
\normalsize
where the {\bf DataCompEnabled: yes} means that tape hardware compression is
64,512 bytes, except the last block of the job which will generally be
shorter. The first thing to try is setting the default block size to zero
using the {\bf mt -f /dev/nst0 defblksize 0} command as shown above.
-On FreeBSD, this would be something like: {\bf mt -f /dev/nsa0 blocksize 0}.
+On FreeBSD, this would be something like: {\bf mt -f /dev/nsa0 blocksize 0}.
On some operating systems with some tape drives, the amount of data that
can be written to the tape and whether or not compression is enabled is
not all, set the density to the maximum by default. On some systems, you
can also get a list of all available density codes with:
{\bf mt -f /dev/nst0 densities} or a similar {\bf mt} command.
-Note, for DLT and SDLT devices, no-compression versus compression is very
+Note, for DLT and SDLT devices, no-compression versus compression is very
often controlled by the density code. On FreeBSD systems, the compression
mode is set using {\bf mt -f /dev/nsa0 comp xxx} where xxx is the
mode you want. In general, see {\bf man mt} for the options available on
your system.
Note, some of the above {\bf mt} commands may not be persistent depending
-on your system configuration. That is they may be reset if a program
+on your system configuration. That is they may be reset if a program
other than Bacula uses the drive or, as is frequently the case, on reboot
of your system.
-
+
If your tape drive requires fixed block sizes (very unusual), you can use the
-following records:
+following records:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
Minimum Block Size = nnn
Maximum Block Size = nnn
-\end{verbatim}
+\end{lstlisting}
\normalsize
in your Storage daemon's Device resource to force Bacula to write fixed size
you have some other strong reasons for using fixed block sizes. As mentioned
above, a small fixed block size of 512 or 1024 bytes will be very inefficient.
Try to set any fixed block size to something like 64,512 bytes or larger if
-your drive will support it.
+your drive will support it.
Also, note that the {\bf Medium Type} field of the output of {\bf tapeinfo}
reports {\bf Not Loaded}, which is not correct. As a consequence, you should
-ignore that field as well as the {\bf Attached Changer} field.
+ignore that field as well as the {\bf Attached Changer} field.
-To recover files from tapes written in fixed block mode, see below.
+To recover files from tapes written in fixed block mode, see below.
\label{FreeBSDTapes}
\subsection{Tape Modes on FreeBSD}
\index[general]{Tape Modes on FreeBSD}
On most FreeBSD systems such as 4.9 and most tape drives, Bacula should run
-with:
+with:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
mt -f /dev/nsa0 seteotmodel 2
mt -f /dev/nsa0 blocksize 0
mt -f /dev/nsa0 comp enable
-\end{verbatim}
+\end{lstlisting}
\normalsize
You might want to put those commands in a startup script to make sure your
tape driver is properly initialized before running Bacula, because
-depending on your system configuration, these modes may be reset if a
+depending on your system configuration, these modes may be reset if a
program other than Bacula uses the drive or when your system is rebooted.
Then according to what the {\bf btape test} command returns, you will probably
-need to set the following (see below for an alternative):
+need to set the following (see below for an alternative):
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
Hardware End of Medium = no
BSF at EOM = yes
Backward Space Record = no
Backward Space File = no
Fast Forward Space File = no
TWO EOF = yes
-\end{verbatim}
+\end{lstlisting}
\normalsize
Then be sure to run some append tests with Bacula where you start and stop
Bacula between appending to the tape, or use {\bf btape} version 1.35.1 or
-greater, which includes simulation of stopping/restarting Bacula.
+greater, which includes simulation of stopping/restarting Bacula.
Please see the file {\bf platforms/freebsd/pthreads-fix.txt} in the main
Bacula directory concerning {\bf important} information concerning
compatibility of Bacula and your system. A much more optimal Device
configuration is shown below, but does not work with all tape drives. Please
-test carefully before putting either into production.
+test carefully before putting either into production.
Note, for FreeBSD 4.10-RELEASE, using a Sony TSL11000 L100 DDS4 with an
autochanger set to variable block size and DCLZ compression, Brian McDonald
the correct values to use are:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
mt -f /dev/nsa0 seteotmodel 1
mt -f /dev/nsa0 blocksize 0
mt -f /dev/nsa0 comp enable
-\end{verbatim}
+\end{lstlisting}
\normalsize
-and
+and
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
Hardware End of Medium = no
BSF at EOM = no
Backward Space Record = no
Backward Space File = no
Fast Forward Space File = yes
TWO EOF = no
-\end{verbatim}
+\end{lstlisting}
\normalsize
This has been confirmed by several other people using different hardware. This
configuration is the preferred one because it uses one EOF and no backspacing
at the end of the tape, which works much more efficiently and reliably with
-modern tape drives.
+modern tape drives.
Finally, here is a Device configuration that Danny Butroyd reports to work
correctly with the Overland Powerloader tape library using LT0-2 and
FreeBSD 5.4-Stable:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
# Overland Powerloader LT02 - 17 slots single drive
Device {
Name = Powerloader
Media Type = LT0-2
Archive Device = /dev/nsa0
- AutomaticMount = yes;
+ AutomaticMount = yes;
AlwaysOpen = yes;
RemovableMedia = yes;
RandomAccess = no;
120T devices on both FreeBSD 5.3 and on NetBSD 3.0. It also works
with Sony AIT-2 drives on FreeBSD.
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
Device {
...
# FreeBSD/NetBSD Specific Settings
Fast Forward Space File = yes
TWO EOF = yes
}
-\end{verbatim}
+\end{lstlisting}
\normalsize
On FreeBSD version 6.0, it is reported that you can even set
\index[general]{Finding Tape Drives and Autochangers on FreeBSD}
On FreeBSD, you can do a {\bf camcontrol devlist} as root to determine what
-drives and autochangers you have. For example,
+drives and autochangers you have. For example,
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
undef# camcontrol devlist
at scbus0 target 2 lun 0 (pass0,sa0)
at scbus0 target 4 lun 0 (pass1,sa1)
at scbus0 target 4 lun 1 (pass2)
-\end{verbatim}
+\end{lstlisting}
\normalsize
from the above, you can determine that there is a tape drive on {\bf /dev/sa0}
and another on {\bf /dev/sa1} in addition since there is a second line for the
drive on {\bf /dev/sa1}, you know can assume that it is the control device for
the autochanger (i.e. {\bf /dev/pass2}). It is also the control device name to
-use when invoking the tapeinfo program. E.g.
+use when invoking the tapeinfo program. E.g.
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
tapeinfo -f /dev/pass2
-\end{verbatim}
+\end{lstlisting}
\normalsize
\label{onstream}
\index[general]{Systems!Using the OnStream driver on Linux}
Bacula version 1.33 (not 1.32x) is now working and ready for testing with the
-OnStream kernel osst driver version 0.9.14 or above. Osst is available from:
+OnStream kernel osst driver version 0.9.14 or above. Osst is available from:
\elink{http://sourceforge.net/projects/osst/}
-{http://sourceforge.net/projects/osst/}.
+{http://sourceforge.net/projects/osst/}.
-To make Bacula work you must first load the new driver then, as root, do:
+To make Bacula work you must first load the new driver then, as root, do:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
mt -f /dev/nosst0 defblksize 32768
-\end{verbatim}
+\end{lstlisting}
\normalsize
Also you must add the following to your Device resource in your Storage
-daemon's conf file:
+daemon's conf file:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
Minimum Block Size = 32768
Maximum Block Size = 32768
-\end{verbatim}
+\end{lstlisting}
\normalsize
Here is a Device specification provided by Michel Meyers that is known to
-work:
+work:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
Device {
Name = "Onstream DI-30"
Media Type = "ADR-30"
AlwaysOpen = yes
Removable Media = yes
}
-\end{verbatim}
+\end{lstlisting}
\normalsize
\section{Hardware Compression on EXB-8900}
at least one more Bacula block to a second tape. Finally, it reads back both
tapes to ensure that the data has been written in a way that Bacula can
recover it. Note, there is also a single tape option as noted below, which you
-should use rather than the two tape test. See below for more details.
+should use rather than the two tape test. See below for more details.
This can be an extremely time consuming process (here it is about 6 hours) to
fill a full tape. Note, that btape writes random data to the tape when it is
the data, especially on slow CPUs. 2. the total amount of data is
approximately the real physical capacity of your tape, regardless of whether
or not the tape drive compression is on or off. This is because random data
-does not compress very much.
+does not compress very much.
To begin this test, you enter the {\bf fill} command and follow the
instructions. There are two options: the simple single tape option and the
multiple tape option. Please use only the simple single tape option because
the multiple tape option still doesn't work totally correctly. If the single
tape option does not succeed, you should correct the problem before using
-Bacula.
+Bacula.
\label{RecoveringFiles}
\section{Recovering Files Written With Fixed Block Sizes}
(default 512) and Bacula with variable blocks (default), then in version
1.32f-x and 1.34 and above, Bacula will fail to recover files because it does
block spacing, and because the block sizes don't agree between your tape drive
-and Bacula it will not work.
+and Bacula it will not work.
The long term solution is to run your drive in variable block mode as
described above. However, if you have written tapes using fixed block sizes,
location is listed in the prompt) using any ASCII editor. Remove all {\bf
VolBlock} lines in the file. When the file is re-written, answer the question,
and Bacula will run without using block positioning, and it should recover
-your files.
+your files.
\label{BlockModes}
\section{Tape Blocking Modes}
bytes than are in the record, only those number of bytes will be returned, but
the entire logical record will have been read (the next read will retrieve the
next record). Thus data from a single write is always returned in a single
-read, and sequentially written records are returned by sequential reads.
+read, and sequentially written records are returned by sequential reads.
Bacula expects fixed block size tape drives to behave as follows: If a write
length is greater than the physical block size of the drive, the write will be
them if possible with Bacula, or you must be ABSOLUTELY certain that you use
fixed block sizes within Bacula that correspond to the physical block size of
the tape drive. This will ensure that Bacula has a one to one correspondence
-between what it writes and the physical record on the tape.
+between what it writes and the physical record on the tape.
Please note that Bacula will not function correctly if it writes a block and
that block is split into two or more physical records on the tape. Bacula
assumes that each write causes a single record to be written, and that it can
sequentially recover each of the blocks it has written by using the same
-number of sequential reads as it had written.
+number of sequential reads as it had written.
\section{Details of Tape Modes}
\index[general]{Modes!Details}
Linux does support both SCSI SPACE Filemarks and End-of-data: When MTEOM
is called in MT\_ST\_FAST\_MTEOM mode, SCSI SPACE End-of-data is used.
In the other case, SCSI SPACE Filemarks with count =
- 8388607 is used.
+ 8388607 is used.
There is no real slow mode like in Solaris - I just expect, that for
older tape drives Filemarks may be slower than End-of-data, but not so
much as in Solaris slow mode. File number is tracked for MTEOM just
\index[general]{Tape Performance}
If you have LTO-3 or LTO-4 drives, you should be able to
fairly good transfer rates; from 60 to 150 MB/second, providing
-you have fast disks; GigaBit Ethernet connections (probably 2); you are
+you have fast disks; GigaBit Ethernet connections (probably 2); you are
running multiple simultaneous jobs; you have Bacula data spooling
enabled; your tape block size is set to 131072 or 262144; and
you have set {\bf Maximum File Size = 5G}.
If you are getting errors such as:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
3992 Bad autochanger "load slot 1, drive 1": ERR=Child exited with code 1.
-\end{verbatim}
+\end{lstlisting}
\normalsize
and you are running your Storage daemon as non-root, then most likely
If you are getting errors such as:
\footnotesize
-\begin{verbatim}
+\begin{lstlisting}
: kernel: st0: MTSETDRVBUFFER only allowed for root
-\end{verbatim}
+\end{lstlisting}
\normalsize
you are most likely running your Storage daemon as non-root, and
Bacula is attempting to set the correct OS buffering to correspond
to your Device resource. Most OSes allow only root to issue this
-ioctl command. In general, the message can be ignored providing
+ioctl command. In general, the message can be ignored providing
you are sure that your OS parameters are properly configured as
-described earlier in this manual. If you are running your Storage daemon
+described earlier in this manual. If you are running your Storage daemon
as root, you should not be getting these system log messages, and if
you are, something is probably wrong.
projects / bacula / docs / blobdiff