Re: Configuring Oracle on RAID 5

"Ian Ledzion" <ian.ledzion_at_xlgbow.com> wrote in message news:98l1li$bsa$1_at_rex.ip-plus.net...
> Am I being thick, or isn't RAID-1 a single disk, and RAID-2 a mirror,
 since
> RAID-5 is 5 disks?

Nothing to do with the number of disks. If it were, RAID-0 would be interesting, would it not??!

I'm not real hot on my RAID numbers, but IIRC (and I think I do) 0 is striping, 1 is mirroring (hence RAID 0+1 is striping AND mirroring), and RAID-5 is striping with parity. Real RAID gurus will tell you all about RAIDS 3, 4 and 6, but if you're like me, you will be asleep before they've finished.

The numbers don'r relate to anything very much, just the standard to which that flavour of RAID adheres.

Incidentally, RAID 5 works very well with 3 disks. Though, since I have shares in Seagate, I think it only fair to say that more is always merrier.

Regards
HJR
>
> "Fred A G" <nospam_at_allowed.localhost> wrote in message
> news:y2fr6.1170$341.4161_at_nntpserver.swip.net...
> >
> > ""Anurag Minocha"" <aminocha_at_herold.com> wrote in message
> > news:EBBA6D3A81229C42981E3AEA79BF5A4E111233_at_jshemail.herold.com...
> > > Hi,
> > > I was wondering that since RAID5 creates one logical volume of disk
 across
> > > multiple drives there is no need to have multiple copies of control
 files
> > > and also multiplexing redo logs is not required.
> > >
> >
> > Raid protects against single-disk failures, nothing more. Have at least
> > two or even three independent control file copies. Regarding redo log
> > files, if you have very basic requirements (few log groups, no
> > archiving(but why!)) then you can have only one raid-1 (mirroring) disk
> > dedicated to redo.
> >
> >
> > > I might be wrong ... I am not sure.
> > >
> > > what care needs to be taken in creating and placing datafiles, redo
 log
> > > files and control files on a RAID 5 machine.
> > > where can i find more information about Oracle on RAID 5 machines.
> > >
> >
> > To me, this seems backward: to buy disks and other hardware and set up a
> > Raid-5 disk array, then figure out what the database physical layout and
> > I/O requirements are.
> >
> > As a very basic setup, I'd say get at least four spindles dedicated to
> > Oracle, one of which is for redo (two out of five, if mirroring). Maybe
> > add one more for Oracle products software. Think IOPS, not storage
> > volume (or, disk is cheap, don't be afraid to "waste" space). Then, if
> > one or more datafile needs more IO put them on a Raid-5 or possibly
> > better Raid 0+1.
> >
> > Regards
> > /Fad
> >
> >
>
>
Received on Tue Mar 13 2001 - 06:07:19 CST