Extentsize/Containers/Tablespace

[Stanley Sinclair]

I am re-doing a database onto V8.7 on a RAID 5 0 array.

That is, in this wildly-striped system, which I'll never understand,
there is one Container in each Tablespace. Most tablespaces are DMS.

ExtentSize is "the number of pages that will be written to a container
before skipping to the next container."

Does this make sense with a single container in each tablespace? Do I
specify EXTENTSIZE = 1? Does the DMS know what to do no matter what I
enter? Should I leave out that parameter?

[m0002a]

Your extent size should be equal to, or a multiple of your RAID stripe
size.

Remember that extent size is expressed in pages and stripe size is
usually in K, so you will have to do the math. For example, if your
RAID stripe size is 64K, then that would be 16 4K pages (assuming the
tablespace page size is 4K) for extent size (or 32 4K pages if you want
a larger multiple).

Check with your UNIX admin to get the RAID stripe size if you can't
find it.

[Art S. Kagel]

Stanley Sinclair wrote:

I am re-doing a database onto V8.7 on a RAID 5 0 array.

That is, in this wildly-striped system, which I'll never understand,
there is one Container in each Tablespace. Most tablespaces are DMS.

ExtentSize is "the number of pages that will be written to a container
before skipping to the next container."

Does this make sense with a single container in each tablespace? Do I
specify EXTENTSIZE = 1? Does the DMS know what to do no matter what I
enter? Should I leave out that parameter?

NO RAID5!! NO RAID5!! NO RAID5!! NO RAID5!! NO RAID5!! NO RAID5!!

See the web site www.baarf.com for several papers (yes mine among them)
about why RAID5 and RDBMS should NEVER be mixed! RAID10 all the way.

Art S. Kagel