I'm a Solaris SA and my Oracle D

[scb]

I'm a Solaris SA and my Oracle DBA can't
answer my question. Maybe you guys can help
me out?

What is the recommended location/layout for
Oracle database files? I've been told that
certain types of files should not be placed
with other certain types of files (example,
indexes should not be placed on same physical
device as data), but I cannot remember the
specifics. Also, that some files should be
placed on one type of RAID and not another.
Also, when possible, that some should be
placed on raw slices. I'd rather not go the
raw route. What I'm trying to is avoid I/O
contention on the disks/filesystems. Are
these recommendations written down somewhere
for me to reference? Any rules of thumb? I'm
not having much luck on my own, and my DBA is
more familiar with Windoze than UNIX/Solaris.
At least that's his excuse. I suspect that he
knows the answers but is holding out on me
(clash of the Solaris SA and Oracle DBA
camps, I guess, and I'm stuck in the middle).

We're running Solaris 2.x, but that shouldn't
make a difference. We're also using UFS, Sun
A1000 (hardware RAID), Sun A5200 (software
RAID), Veritas Volume Manager v3.x.x, and
Oracle 8.0.5/8.0.6, 8i, and 9i. Generically
speaking, none of this should make a
difference either. But they're options we
have that we can play with.

While I've got your attention, do any of you
have experience with Oracle 8.0.6 on Solaris
2.6 and using the "forcedirectio" option to
the mount command? Any warnings, gotcha's,
performance improvements/degradations using
this? Any Oracle-related filesystems that
should NOT be mounted with this option. We're
NOT using Veritas File System (VxFS), Quick
I/O, raw, or other methods on this particular
box and we don't have these as options; it's
basic VxVM RAID (O, 1, and 0+1) on vanilla
UFS.

Thanks,
SCB

 

[robwall7]

I'm a new ORACLE DBA and the name of the answer you are looking for is OFA (Optimal Flexible Architecture) in combination to the Physical Database Layout. The number of available disk volumes that can be dedicated to the database will be a major factor. The DBA Handbook has "The Dream Database Physical Layout: the 22-Disk Solution" and all the way down to "the 7-Disk Compromise".

This is the starting point, and since I am a new DBA, the layout from hear seems to be as much art as science.

Good Luck

 

[jimbopalmer]

OFA is a very good way to layout disks My a1000 has a 20 meg RAM Cache, if the redo logs or /arch are on your a1000 consider having the redos be less than 20 meg in size, so the entire disk copy can happen at RAM speeds.

Oracle likes you to use'multiplexed' redos not RAID, Data and Indexes on different drives or RAID sets (note: one tablespaces indexes can be with another tablespaces data)

the applications can be RAID 0 assuming you back them up, only developers are changing that disk.

(tell them to commit often on RAID with a RAM cache, this is againist the older practice of commiting rarely if going right to disk, but you want all disk transfers to be smaller than your RAM cache.) I tried to remain child-like, all I acheived was childish.

 

[alexhu]

Seems like you're doing the DBA's job. He should be telling you the layout and how big to make each partition etc. It is all in the documentation he has, so theres no excuse. Beware of when the application is live and poor performance is down to bad disk layout - guess who'll get the blame ?

Alex