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:
  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

Basically, what I am learning is that there is no "cut and dried" answer, it all depends on things such as nature of system (lots of reads, lots of writes, etc.), factor importance (performance vs. cost vs. reliability), and others. Obviously, RAID0+1 is the "best" in terms of performance and reliability, but someone here brought the terabyte word the other day so even if disk is cheap, that is still alot of disk, especially using RAID0+1. So far from our assessment, since our system is pretty even combo of reads and writes I think we have decided to go with a combination and configure so that we keep the really write intensive things such as redo logs OFF RAID5 and put the data files on RAID5 and try to improve the performance as much as we can by adjusting things like stripe size and write "caches". We have a new develop server coming so will probably try to do some benchmarking against to determine if we get the performance we want.

Also, the lantimes site listed above has an article about HP's AutoRAID that may be worth looking into.

I know I don't have all (or even any) of the answers but feel free to respond directly to me with questions (or suggestions) and maybe we can assist each other. Actually, anyone else that has input feel free (anyone out there from ORACLE or HP).

For all its worth,
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