--> ... you have a filesystem of lvm blocksize smaller than the raid-strip size 
...

I would rather say the write block size *must* be N times the raid-stripe
size for RAID-5! If the array in question is RAID-5 and lets assume 16 kB
stripe - neither 64 kB write-block (read-before-write) nor 128 kB block
(one full-write + one read-before-write) will provide optimal performance
on a typical DAS arrays.
Either good SAN array should be used or member set *must* be 2^n+1 (3,5,9)
disks.

Zlatko Krastev
IT Consultant






Remco Post <r.post AT SARA DOT NL>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
03.09.2003 21:34
Please respond to "ADSM: Dist Stor Manager"


        To:     ADSM-L AT VM.MARIST DOT EDU
        cc:
        Subject:        Re: DSMFMT takes forever ( 15 hours). 100 gb


On Wednesday, Sep 3, 2003, at 18:22 Europe/Amsterdam, Ochs, Duane wrote:

> Does anyone know of or had problems with formatting additional space
> for
> diskpools ?
>
> TSM server : AIX 5.1 ML3 64-bit enabled. 2GB memory 2 cpu H80
>
> Disk type : 6 member raid set about 700 GB
>
> JFS2
>
> Trying to format 100gb diskpool. Each time I have tried it brings the
> TSM
> server to almost a stand still. TSM is up on the box but nothing is
> running
> during 8 hours of the format. Should be more than enough time to format
> 100gb of space.
>
> Any ideas ?

possibly, you have a filesystem of lvm blocksize smaller than the
raid-strip size, this especially a problem with the ssa raid adpaters
(those suck big time IMNSHO) Using a huge blocksize helps....

>> Duane Ochs
>> Enterprise Computing
>>
>> Quad/Graphics
>>
>> Sussex, Wisconsin
>> 414-566-2375 phone
>> 414-917-0736 beeper
>> Duane.Ochs AT qg DOT com
>> www.QG.com
>>
>>
>>
--
Met vriendelijke groeten,

Remco Post

SARA - Reken- en Netwerkdiensten                      http://www.sara.nl
High Performance Computing  Tel. +31 20 592 8008    Fax. +31 20 668 3167

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