Stripe size

[Lai Nee Shyang_1]

Hi there,

I've a machine runing SAP4.5 with oracle 8.0.5.2.1. Currently we are using lvm striping with 64K stripe size. As we are using XP512 storage systems, I learn that internally the disks are already stripe. Someone suggest we convert the entire system into a giant VG to acheive better distribution of datafiles and avoid "hot" spots.
My question is:
1. Has anyone out there done this for a system with 3 Tb size?
2. What is the effect of over striping, or if the stripe size is small??

Appreciate if anyone can share his/her experience.

Thank you. Have a nice day.

Lai

[KapilRaj]

the bigger the strip size , the faster the filesystem &less efficient. The smaller , the slower & more efficient.

kaps

[Stephen Serbe]

Are you using "business copy" on the xp512? There maybe issues with managing volume groups snapping a copy of the database for backups...
If you have one large VG how do you stripe the additional disks you add for growth?? Are all the disks on your XP256 the same size/speed? We use one VG for 15 Gb / 12k RPM disks where we place Oracle indexes. We use another VG for Oracle tables - totally separate disks - 73 Gb / 10 RPM... and we place our archive logs on separate physical disks... There are many other similiar questions/issues... think this over carefully before the plunge. Stephen

[Lai Nee Shyang_1]

Hi Stephen,

Yes, we are using BC copy on the 512 for backup. I guess if we plunge into the strategy of using 1 giant VG, the BC copy may have to be reconfigure.

I'm not really sure about scalability with the giant VG. According to HP's white paper, XP512 is able to spread the data on existing disks to new disks added. This will prevent "hot" spots forming up on the new disks.

I kindof like the idea segregating the tables, indexes, archive logs on seperate vgs. I'll think about it.

Thanks for sharing.

Lai