UNIX for Dummies Questions & Answers

Hi Everyone,

Can someone tell me the effect of the pp size of the volume group created for Oracle data.

It would seem that creating small pp's will cause more overhead. What if you make the pp to large? What should I base this size on?

Thanks,

This is a classic question. It really depends on the size of your data. If your data is in hundreds of small files, then a smaller size will allow you to waste less space because there will be a smaller amount of left over disk per chunk when the chunks are smaller.

If you have large data chunks (files), then larger sizes for pp will be just fine. It really depends on your data. It is usually good to pick the default size or a little larger.

This question is very similar to the Extent size for Volumes. On my HPUX system the default size is 4MB. Which is fine for most cases, however, I have seen cases where it was 8MB and even 2MB. All depending on the data.

Thanks for reply,

I am going to be storing 10-14 Oracle datafiles that are 500mb each on this volume group.

The default is 4mb I was looking at 64mb, but I can also go to 256mb. If its the size of the datafiles that gets allocated, would if be safe to say 512mb would work?

I would never go above 256, I believe there some issues with this.

I have systems with oracle DBs that are striped 128K across 4 disks. You should be good with 64K or 128K. My DBs are between 200GB and 500GB.

ok, I'm lost.

The only options I have to create a volume group with a physical partition size in AIX 4.3.3 is 2mb thru 1024mb. I don't see a 128k anywhere?