On Thu, Mar 3, 2011 at 4:11 PM, Fabio Napoleoni - ZENIT <fabio AT zenit DOT 
org> wrote:
>
> Il giorno 03/mar/2011, alle ore 20.53, Alan Brown ha scritto:
>
>> Fabio Napoleoni - ZENIT wrote:
>>
>>> Thank you for your analysis, after that I think that the problem is not the 
>>> nfs overhead, because the despooling phase (over nfs filsystem) has a 
>>> transfer rate of 7.3 MBps, so it's fine. Instead the first phase (bacula-fd 
>>> -> bacula-sd) happens at 1.2 MBps which is very poor value I think.
>>
>> Is this a full backup?
>
> Yes it is.
>
>> You can't get accurate results with anything else.
>>
>>      compression=GZIP # compress backup
>>
>> This will have a MARKED effect on your speeds. Consider switching it off and 
>> see how fast things go.
>
> I tried to disable both compression and signature with this results:
>
> Job write elapsed time = 00:03:31, Transfer rate = 7.918 M Bytes/second
> Despooling elapsed time = 00:03:50, Transfer rate = 7.272 M Bytes/second
>
> This is the performances with signature only (no compression)
>
> Job write elapsed time = 00:03:42, Transfer rate = 7.528 M Bytes/second
>
> And this is the performances with compression only (no signature)
>
> Job write elapsed time = 00:12:51, Transfer rate = 1.322 M Bytes/second
>
> So the poor throughput is given by software compression. I don't know what to 
> choose in the speed vs space tradeoff. Ideally the best option could be 
> compression on the storage director (it has more powerful hardware than this 
> client) but I think that bacula currently doesn't support this feature.
>

You could do that with filesystem compression. There are a few options
for that. Although I admit none of them are in the mainline kernel.

John

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