Re: [Bacula-users] FreeBSD 9 and ZFS with compression

Hello again,

On Thu, Feb 9, 2012 at 12:22 PM, Steven Schlansker <steven AT likeness DOT com> wrote:

On Feb 9, 2012, at 10:07 AM, Martin Simmons wrote:

>>>>>> On Wed, 8 Feb 2012 20:22:46 -0600, Mark said:
>>
>> Just checking to see if people are having success with storage daemon
>> running on FreeBSD 9.0 with ZFS and compression enabled? I ask because I'm
>> having issues with the backups completing without any errors reported, but
>> then an immediate restore attempt fails due to block checksum mismatches,
>> or trying something like 'bls -j -v -V Full-0079 FileStorage1' will fail
>> and exit with a block checksum mismatch.
>>
>> The pool is a raidz1 made up of 5 1.5TB drives. I can run a scrub, get a
>> clean result, run a backup, then have a restore from that backup fail (only
>> for larger backups, small ones seem fine). A scrub run after that will
>> also report errors, usually 1 or 2 out of roughly 600GB of data, and it
>> will show them as repaired. I'm just trying to determine if I'm being
>> bitten by the SATA controller, it's an ' <ATI IXP700 AHCI SATA controller>'
>> and I have to set the storage type to IDE instead of AHCI and set
>> 'hint.ahci.0.msi=0' in loader.conf or the system can't even see the drives.
>> Or maybe what I'm trying here is a bad idea? I'd just like the
>> compression without the overhead and slowdown on the clients that comes
>> from enabling compression in the fileset. I'm a FreeBSD neophyte, is the
>> SATA/AHCI stuff just not good yet or would much better results be likely
>> with a newer board/controller?
>
> I think your ZFS setup should work fine, but I don't know about your specific
> hardware.
>
> You must have hardware problems -- not necessarily in the SATA controller
> though. The block checksum mismatches suggest that the wrong data was written
> to the disk.
>
> Have you got EC RAM? Have you run Memtest86?

I run a FreeBSD 9.0 setup with ZFS (8 drives in raidz2). Compression and dedup on.

It runs like a champ, no problems at all so far. I'll second the guess that you
have hardware problems.

Thank you Martin and Steven for your replies. I'm inclined to agree with you, as a motherboard swapout has resolved the issue. I don't know if it's the different RAM or SATA controller, but everything else (cables, drives, etc) is the same and the problem is gone. Thanks, I just wanted to make sure I wasn't doing something sketchy, but it certainly seemed like it was a logical and pretty simple setup.

Steven, out of curiosity, do you see any benefit with dedup (assuming that bacula volumes are the only thing on a given zfs volume). I did some initial trials and it appeared that bacula savesets don't dedup much, if at all, and some searching around pointed to the bacula volume format writing a unique value (was it jobid?) to every block, so no two blocks are ever the same. I'd backup hundreds of gigs of data and the dedupratio always remained 1.00x.

Regards,

Mark

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Re: [Bacula-users] FreeBSD 9 and ZFS with compression - should be fine?