RE: OFA and Shared Storage

Hi,

I've tended to have performance problems with RAID-5 (slow write times). Does SAN make this any better, ie. with large disk caches etc?

With SAN, do the redo logs still hit the spindles when a commit is issued (for example)? I seem to recall that the EMC Symmetrix considers the write to be done when the write request is in its cache and not necessarily on the disk.

Cheers,
Craig.

At 10:54 AM 22/09/2003 -0800, Mladen Gogala wrote:
>Files are kept safe simply by RAID-5 mechanism. RAID-5 protects against any
>single disk failure (double disk failure can wipe it all out) and that is
>precisely
>why Mogens is such a zealous proponent of RAID-5 systems.
>
>--
>Mladen Gogala
>Oracle DBA
>
>
>
> > -----Original Message-----
> > From: ml-errors_at_fatcity.com [mailto:ml-errors_at_fatcity.com] On
> > Behalf Of rgaffuri_at_cox.net
> > Sent: Monday, September 22, 2003 2:05 PM
> > To: Multiple recipients of list ORACLE-L
> > Subject: OFA and Shared Storage
> >
> >
> > I read some posts on here with shared storage such as SAN and
> > Network Appliances its no longer necessary to multiplex
> > datafiles on different disks, since the storage array handles
> > that for you.
> >
> > How do you ensure that control files and redo log files are
> > kept safely apart so that no one disk failure in the shared
> > storage can take them all out?
> >
> > According to the OFA(well the abbreviated version I have in
> > front of me) 4-5 disks is optimal for multiplexing. Does this
> > no longer apply with shared storage? How do you ensure
> > database available with shared storage? if your not
> > multiplexing datafiles?
> >
> > I may have read some peoples posts incorrectly. Im just
> > digging into backup and recovery.
> >
> > --
> > Please see the official ORACLE-L FAQ: http://www.orafaq.net
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> > Author: <rgaffuri_at_cox.net
> > INET: rgaffuri_at_cox.net
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Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Craig Munday
  INET: cmunday_at_bigpond.net.au

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