Re: RAID experience/recommendations

Paul,

Not sure when you posted your question but I have been researching the same question for the last few weeks and interestingly enough we too are using 7.3x on HP9000 series machines. I have gotten several responses as well as came across some good white papers, including:

Specific to Oracle: (from ORACLE)
  Configuring Oracle7 Server for VLDB at http://www.europa.com/~orapub/

         (very good)

Then some general to RAID:

    http://www.lantimes.com/lantimes/features/srraid.html
    http://www.mindspring.com/~hayden/sunraid.htm
    http://www.mindspring.com/~hayden/raid05.htm

All in all, the answers create more questions, such as: factor importance (performance vs. reliability vs. cost) and what is the nature of your system (lots of reads, lots of writes, etc), but basically, from what I'm seeing, RAID0+1 is the "best" but RAID5 is workable especially when you consider that you can configure things such as file distribution, stripe size and write cache-ing to help performance.

Since, the nature of operation systems are an "even" mix of read and writes I think we are going to start with a mix of RAID and ensure that we keep certain things like redo logs and other write intensive files OFF of RAID5, and begin with, at least on our development server, by putting the dbf files on RAID5 and try to determine what kind of performance hit we take (that whole 5-7 (depending on where you read it) step write process). I know that they say disk is cheap, but even so someone brought up the "terabyte" word the other day and at RAID0+1 thats alotta disk.

Actually the LAN times article discusses HPs AutoRAID which might be something to consider.

I don't have all (or even any) of the answers but feel free to respond to me directly for advice (or even better with suggestions). Actually I would welcome input from anyone else as well (anyone out there from HP or ORACLE). Thanks,

neal.nachtigall_at_lodgenet.com

Barry P. Grove <grovebg_at_iSTAR.ca> wrote in article <34A1853C.54EF_at_iSTAR.ca>...
> CLOSEP1_at_westat.com wrote:
> >
> > Thanks for any and all input anyone may have.
> >
> > We have Oracle v7.3x Enterprise Server running on our HP9000 server.
> > We are in the process of reviewing mirroring and RAID options that we
> > wish to implement early next year.
> > I vaguely remember Oracle recommendations against RAID 5 and in favor
 of
> > RAID 0+1, although I couldn't dig up any specific info.
> > We are looking at both hardware and software mirroring and RAID
 options.
> > Does Oracle have any white paper re: using RAID with Oracle databases?
> >
> > Thanks in advance for all replies.
> >
> > - Paul Close (Westat)
>
> Hi Paul:
>
> At work, I'm using DEC Alpha 2100/250 servers with 512MB memory,
> DEC HSZ40 Raid controllers with 32MB cache and about 128GB disk
> online for multiple 12GB PeopleSoft databases. Originally I had
> set up the drives for RAID5, but found the sustained write rate
> of <2MB/sec unbearable; the sustained read rate of 7MB/sec was ok.
> Had to change to RAID0+1 to get performance I needed, not only
> for our production system, but also to refresh a read-only reporting
> database nightly from production in a reasonable amount of time.
> Of course you use a lot more disk for RAID0+1 (striped mirrors)
> than RAID5, but disk is getting really cheap. Just our RAID
> controllers and enclosures seem to stay pricey.
>
> I'm now using RAID5 only for relatively static history tables that
> are refreshed/updated infrequently.
>
> Hope this helps.
>
> --
> Barry P. Grove BarrySoft Systems Applications
> grovebg_at_iSTAR.ca (604)929-5433
> Developer, Oracle DBA, Unix Sysadmin North Vancouver, BC, V7H-2G4
>
Received on Fri Dec 26 1997 - 00:00:00 CST