On Wed, 5 Sep 2007, Justin Piszcz wrote:

>
>
> On Wed, 5 Sep 2007, Parker, Matthew wrote:
>
>> What type of benchmark testing are you looking for?
>>
>> -----Original Message-----
>> From: veritas-bu-bounces AT mailman.eng.auburn DOT edu 
>> [mailto:veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf Of 
>> Justin Piszcz
>> Sent: Wednesday, September 05, 2007 4:36 AM
>> To: veritas-bu AT mailman.eng.auburn DOT edu
>> Subject: [Veritas-bu] Tuning backups.
>>
>> There are several ways to tune backups.
>>
>> 1. NET_BUFFER_SZ
>> 2. SIZE_DATA_BUFFERS
>> 3. NUM_DATA_BUFFERS
>>
>> While these help a little, I found by reading the NBU6 optimization document 
>> I improved speed by 2x in some cases (need to do some more
>> verification) using 256k buffers in the kernel (Linux) st driver rather than 
>> the default of 32k and also using more of them.
>>
>> Anyone here do a LOT of benchmark testing?
>
> So far, it would appear that using general optimizations in NetBackup
> only help so much, such as the ones mentioned above with the exception
> of NET_BUFFER_SZ, I still need to look into that one.
>
> The buffers in the kernel appear to help much more, in Linux 2.4 the
> default buffers for the st tape driver are 32k and there's four of them.
>
> I want to know every possible tunable parameter and its effect on the
> system for the fastest backup possible.
>
> Justin.
>
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>

In particular:

9.3.1. st boot parameters

st=xxx[,yyy] where xxx is one of the following:
buffer_kbs:<n>
write_threshold_kbs:<n>
max_buffers:<n>
max_sg_segs:<n>

(The old boot parameters st=aa[,bb[,cc[,dd]]] supported but deprecated)


http://www.linux.com/base/ldp/howto/SCSI-2.4-HOWTO/st.html
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