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Oracle and Partitioning

Massimo_37
Frequent Advisor

Oracle and Partitioning

We have a HP UX 10.2 server with 2 18G drives (One mirrored). We are planning to import the database (Oracle 7.3.4) on this new server from our old server , after installing Oracle. On our old server we have 5 1G discs and 1 2G disc. The database occupies 5 logical volumes (/disc1.../disc5) . /disc5 contains the export from the daily backup. The /disc1 has SYSTEM table space, /disc2 has USER1 and /disc3 has /USER2 tablespace. /disc4 has extension of USER1 and USER2.All the logical volumes are 1 G each.

When I create partitions on the new server should I follow the same pattern( ie create 3or 4 voulmes for databse and 1 for backup), as on the old server. Or should I create one big logical volume of say 6G for all the tablespaces ? (Please note that we have only one physical disk of 18G unlike 6 disks on the olde server)
Oracle manual recommends that the database be spread across 3 mount points. Does this need to be on 3 different logical volumes ? WHich is the best way - performance wise etc. Many thanks in advance
4 REPLIES
Geoff Wild
Honored Contributor

Re: Oracle and Partitioning

Here's a little doc on Oracle 8i Requirements on HP-UX that may help you plan.

For performance, it is generally better to have redo on separate disks...

Rgds...Geoff
Proverbs 3:5,6 Trust in the Lord with all your heart and lean not on your own understanding; in all your ways acknowledge him, and he will make all your paths straight.
Jean-Luc Oudart
Honored Contributor

Re: Oracle and Partitioning

As metioned if at all possibel separate redo from the tablespaces.

check the attached document for when you can get more disks to spread the load.

Regards
Jean-Luc
fiat lux
Yogeeraj_1
Honored Contributor

Re: Oracle and Partitioning

hi,

please allow me to also add the following:

You should basically follow the following guidelines:

o no raid, raid 0 or raid 0+1 for online redo logs AND control files.
You should still let us multiplex them ourselves even if you mirror them. We have more opportunities for failure if the raid subsystem reports a "warning" back to us -- if we have multiplexed them -- we are OK with that.


o no raid or raid 0 for temporary datafiles (used with temporary tablespaces). no raid/raid 0 is sufficient. If you lose these, who cares? You want speed on these, not reliability. If a disk fails, drop and recreate temp elsewhere.

o no raid, raid 0 or raid 0+1 for archive. Again, let us multiplex if you use no raid or raid 0, let the OS do it (different from online redo log here) if you use 0+1.

o raid 0+1 for rollback. It get written to lots. It is important to have protected. We cannot multiplex them so let the OS do it. Use this for datafiles you believe will be HEAVILY written. Bear in mind, we buffer writes to datafiles, they happen in the background so the poor write performance of raid 5 is usually OK except for the heavily written files (such as rollback).

o raid 5 (unless you can do raid 0+1 for all of course) for datafiles that experience what you determine to be "medium" or "moderate" write activity. Since this happens in the background typcially (not with direct path loads and such) -- raid 5 can typically be safely used with these. As these files represent the BULK of your database and the above represent the smaller part -- you achieve most of the cost saving without impacting performance too much.


(raid 0 = stripes, raid 1 = mirrors, raid 5 = striping+parity):


Try to dedicate specific devices to

o online redo
o archive
o temp

they should not have to share their devices with others in a "perfect" world (even with eachother).

also consider upgrading to at least 8.1.7.4.

hope this helps too!
regards
Yogeeraj
No person was ever honoured for what he received. Honour has been the reward for what he gave (clavin coolidge)
Nicolas Dumeige
Esteemed Contributor

Re: Oracle and Partitioning

Hello,

I'm afraid that with only two disks the IO load will not be well balanced. If you use only one disk for Oracle, that's even worse !!! Even with a better disk, 6 to 1 disk installation : you should anticipate IO contention and performance trouble.

If you don't use anymore you're old server, use it's disk to spread the load.

Cheers

Nicolas
All different, all Unix