disk physical extent size for oracle 10g

[Leah Chow]

My company just purchased a new HPUX RX6600 server with B.11.31 U ia64 OS. i am planning to install oracle 10g on the server.

My question is the disk on the server is 136gb, when i create VG for oracle data file, what is the physical extent size i should choose?

Thanks for your help
Leah

[Hein van den Heuvel · Accepted solution]

Pick something large. Too many folks have been burned by choosing too small, or accepting a default and then no longer being to add disks to the VG running into a max_pe wall.

Please GOOGLE for MAX_PE and read-around some. Some back with DETAILED questions if you thing the general articles ddo not help enough.. but then you would know why those articles could not help.

If you do re-reply PLEASE provide details like HOW MANY drives, initially and the maximum over time. And HOW are they connected. I get the impression you'll be using direct connect scsi drives, but maybe there is a controlled involved?

And you have to ask yourself WHY even use LVM? Force of habit? What added value do you expect it to offer for your deployment?
Should you not consider 'giving the disks to Oracle' though Oracle ASM and not worry about extents?

Good luck,
Hein van den Heuvel
HvdH performance consulting

[Pete Randall]

You can just let it default and the proper size for that particular disk will be calculated and used. However, if you have any possibility at all of wanting to expand that VG using larger disks in the future, you would do well do double or quadruple the default.


Pete

[TTr]

The PE size has to do with the geometry (size) of the disk and the creation of logical volumes in LVM. The size has some impact if you use extend based striping but that's about it. I think for a disk this size, the default would be 16MB but you can make it smaller or larger if you want. You can also adjust the number of extends on the disk in case later on you want to add 300GB disks in the same VG as with the 146GB ones.