Success: Bacula

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Success: Bacula

[nia]
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Success: Bacula

Postby ap2010 » Thu May 13, 2010 5:27 am

For what it's worth, I am using bacula for several months now on top of mhvtl.

If you use the two additional settings for the tape devices, as mentioned in the documentation

# Needed for mhvtl tape drives
Hardware End of Medium = No
Fast Forward Space File = No

it works fine, no problems.

Albert
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Re: Success: Bacula

Postby nia » Thu May 13, 2010 9:55 pm

Hi,

It seems like I have the same issues with TSM when it comes to EOM and FSR
viewtopic.php?f=34&t=125
Do you know why bypassing these in Bacula allow mhvtl to work correctly ? I am just trying to figure out the cause for TSM .. 
I hear that Bacula was originally derived from an old adsm code back in the days, so it maybe behaving similar to TSM now ---Don't quote me, I could be wrong. :lol:
~nia
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Re: Success: Bacula

Postby ap2010 » Fri May 14, 2010 2:50 am

In short, I just followed the manual of mhvtl. I had problems using the implementation of mhvtl in stgt,
which is incomplete. When I switched to mhvtl I just took over the advice of adding these settings. However, I just tried bacula
without these settings, and it still works (at least it looks like that so far). So the implementation of mhvtl is more complete than expected.

FYI, this is what the bacula manual says about these settings:

Fast Forward Space File = yes/no
If No, the archive device is not required to support keeping track of the file number (MTIOCGET ioctl) during forward space file. If Yes, the archive device must support the ioctl MTFSF call, which virtually all drivers support, but in addition, your SCSI driver must keep track of the file number on the tape and report it back correctly by the MTIOCGET ioctl. Note, some SCSI drivers will correctly forward space, but they do not keep track of the file number or more seriously, they do not report end of medium.

Hardware End of Medium = yes/no
If No, the archive device is not required to support end of medium ioctl request, and the storage daemon will use the forward space file function to find the end of the recorded data. If Yes, the archive device must support the ioctl MTEOM call, which will position the tape to the end of the recorded data. In addition, your SCSI driver must keep track of the file number on the tape and report it back correctly by the MTIOCGET ioctl. Note, some SCSI drivers will correctly forward space to the end of the recorded data, but they do not keep track of the file number. On Linux machines, the SCSI driver has a fast-eod option, which if set will cause the driver to lose track of the file number. You should ensure that this option is always turned off using the mt program.

Default setting for Hardware End of Medium is Yes. This function is used before appending to a tape to ensure that no previously written data is lost. We recommend if you have a non-standard or unusual tape drive that you use the btape program to test your drive to see whether or not it supports this function. All modern (after 1998) tape drives support this feature. 


But if this works fine now, as it seems now, then I would say your problem is not related to this.
ap2010
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Re: Success: Bacula

Postby ap2010 » Fri May 14, 2010 1:44 pm

One more addition for the bacula-sd.conf file, which is actually a general problem.

The line:
Alert Command = "sh -c 'tapeinfo -f %c |grep TapeAlert|cat'"

doesn't work, as tapeinfo only works with the generic device of the tape.
In order to find it for e.g. /dev/st0 do a "lsscsi -g | grep st0" then you'll find the general 
device (/dev/sg2 or something like that). That's what you need to fill in instead of %c.

As said, it is not a mhvtl problem, but a general problem with bacula. This way tapealert works.

Albert
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Re: Success: Bacula

Postby nia » Sat May 15, 2010 12:41 pm

Thanks Albert .. This was very helpful. :)
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