On 08/09/2010 12:39 AM, Joseph Dickson wrote:
> Greetings..
>
> I'm using Bacula in an all-disk based environment, using a disk based
> autochanger script. I'm wondering if anyone has come up with a magic recipe
> for dealing with the compression issues that are inherent with this type of
> strategy..
>
> What I'm talking about mostly is that bacula-fd performance with software
> compression on is pretty slow, which I think I've read can be attributed to
> the single threaded compression algorithm that is being used.. I would much
> rather stream the data from the hosts uncompressed and then compress it once
> it reaches the SD, since my backup server tends to be fairly beefy compared
> to many of my hosts..
>
> What have other people done to combat this issue? Is it worth my time
> investigating some of the virtual tape library software out there for Linux,
> which presumably implements reasonable compression on the virtual tape lib
> side? Or are people perhaps using a transparent compression filesystem with
> good results?
>
> Just trying to get a feel for what people have found works.. need to reduce
> the window to backup each host (i.e. up the throughput from the 2-3MB/sec I'm
> getting) but don't want to sacrifice the space of doing completely without
> compression :)
>
> Thanks!
>
> Joe
>
Hi Joe,
During the time the SD compression possibility exist, I'm using compression
also on certain windows server.
Some tests have prove to me that using a GZIP2 param in fileset is sufficient
to obtain a good ratio between speed and
compression. The normal GZIP set gzip to it's default compression level 6.
Which consume more cpu (and time for a 1 ou 0.5% gain
on total bytes )
This is what I obtain for a low-end server Win2K3 2GB Ram (P4 Dualcore 3.Ghz)
with 2 sata raid soft harddrive.
Client: "chesne-fd" 3.0.2 (18Jul09) Linux,Cross-compile,Win32
FileSet: "FileSet-Chesne-Full" 2008-05-11 15:52:17
Pool: "Pool_FileWeeklyCHESNE" (From Job resource)
Catalog: "MyCatalog" (From Client resource)
Storage: "Store_FSCHESNE_WEEK" (From Job resource)
Scheduled time: 07-Aug-2010 18:00:00
Start time: 07-Aug-2010 18:01:46
End time: 07-Aug-2010 18:31:01
Elapsed time: 29 mins 15 secs
Priority: 9
FD Files Written: 75,110
SD Files Written: 75,110
FD Bytes Written: 9,931,147,048 (9.931 GB)
SD Bytes Written: 9,945,142,186 (9.945 GB)
Rate: 5658.8 KB/s
Software Compression: 46.3 %
VSS: yes
Encryption: no
Accurate: no
But it really depend on what type of data you have.
My data on linux compress only at 10% and typical speed drop from a 40MB/s to
18MB/s with a gzip2 level.
--
Bruno Friedmann br...@ioda-net.ch
Ioda-Net Sàrl www.ioda-net.ch
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User www.ioda.net/r/osu
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(bruno.friedmann (at) fsfe.org )
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