system file placement

[kburrows]

Hi Everyone,

I am trying to place the datafiles correctly to avoid any problems.

Question:
Where do the system datafiles belong.

Here is my setup

Disk1 - unix executables, oracle executables
Disk2 - system, tools, redologs
Disk3 - rollback
Disk4 - indexes
Disk5 - application data, temp, users

All the material I can find doesn't tell me where the system tbsp belongs, it seems to be hit frequently.

Where would you place it? Or any other suggestions welcome.

Thanks,
Kathy

[marist89]

The SYSTEM tablespace is just like any other data file (in this perspective, anyway). It needs to be monitored for I/O utilization and distributed appropriately. You should monitor I/O on your server over time and determine if one or more mount points are more busy thany the others. If so, dig into the file placement and try to spread your I/O load around to other devices.

[julian]

Are you planning on having your DB on archivelog mode? If so, think of the log files.

More important, I prefer to have the redologs on separate disks. Not a good idea to have them on the same disk with the system file, not good at all.

[kburrows]

Julian,
Why do you say

"Not a good idea to have them on the same disk with the system file, not good at all."

I am following the disk placement rec's from revealnet. Here is their five disk scenario.

disk1 - executables, system datafile, redo logs, controlfile
disk2 - app data files, temp, controlfile
disk3 - app index files, controlfile
disk4 - rollback, export
disk5 - archive

What is your reasoning?


Jeff,
Also is system datafiles are treated like app data files then I should put them on the same disk as the app data files, right. It seems there would be lots of contention?

[marist89]

Originally posted by kburrows

Jeff,
Also is system datafiles are treated like app data files then I should put them on the same disk as the app data files, right. It seems there would be lots of contention?

No, not necessarily. Just as I wouldn't put all my DATA data files on one disk, I wouldn't put my SYSTEM data files on one disk. You can initially set your system up as described, but monitor for I/O hotspots.

[julian]

Originally posted by kburrows
Julian,
Why do you say

"Not a good idea to have them on the same disk with the system file, not good at all."

You must ensure that no other process, not even ARC, will be able to access the log file disks while LGWR is writing to them.

I suggest you read the following:

http://www.ixora.com.au/tips/creatio..._log_files.htm