Urgent : Create tablespace performance problem

From: Gilles PARC <gparc_at_online.fr>
Date: Wed, 25 Jun 2003 12:45:15 -0700
Message-ID: <F001.005B9A8B.20030625122750@fatcity.com>

Hi Listers,

Configuration :

Software : Aix 4.3.3 / Oracle 9.2.0.3
Hardware ; 6 CPU, 16 Go RAM,

                    DAS clarriion FC4500 with 2 Storage Processors (SP)
                    1 Fibre channel link by SP
                    10 x 36 Go Disks
                     512 Mo of cache

Disk configuration :
1 RAID group raid1 (2 disks) Lun bound to SPA --> hdisk1 --> VG01 1 RAID group raid5 (9 disks - stripe size 128Ko) Lun bound to SPB --> hdisk2 --> VG02
1 RAID group raid5 (6 disks - stripe size 64Ko) Lun bound to SPA --> hdisk3 --> VG03
1 RAID group raid1(2disks) Lun bound to SPB --> hdisk4 --> VG04 1 Hot spare

Now the problem :
Nota : Oracle block size is 8Ko

I created 8 x 8 Go raw logical volumes (aka raw devices) on VG02 when I create a 64 Go tablespace (8 datafiles) on these, it takes 2h30

then I created 10 x 8Go raw logical volumes on VG03 But when I create a 80 Go tablespace (10 datafiles) on these, it takes only 30 minutes.
That's 5 times less for a bigger size !!

What can be the reason ?

So far, the differences I see are :
- VG and so LVs are attached to a different controller (SPA vs SPB)

stripe size is different (64k vs 128K)
stripe width is different (6 disks vs 9 disks)
VG Partition Size is different (256 Mo vs 512 Mo)

Which one do you think is the main culprit ? As I'm not on site and I don't want to change all at once, I plan to ask first for a double check of the FC links, controllers and Luns configuration
But after that except asking to rebuild with the same stripe size , width and PPsize,
I'm at a loss.

Any ideas ? except BAARF of course ;-))

Thanks in advance

Gilles Parc

carpe diem !!

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Author: Gilles PARC
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Received on Wed Jun 25 2003 - 14:45:15 CDT