Oracle-L: Re: How many levels or redo mirroring ?

From: Bruce Pihlamae <bpihlama_at_NLA.GOV.AU>
Date: Mon, 22 Jan 1996 09:01:34 +0000
Message-Id: <9601212214.AA22280@alice.jcc.com>

> If I'm running my entire database (database, control, and redolog
> files) on RAID 0+1, does it make sense to have Oracle mirror the redo
> logs (in addition to the RAID protection) ?

If all your disks are already mirrored (RAID1) then don't bother doing Oracle mirroring on the REDO logs. Its extra overhead you don't need.

If you have only striped (RAID0) then you have no recoverability so you should using the Oracle REDO log mirroring.

Having said that, it is not good practice to use RAID1 mirroring on 'write only' files because of the overhead and slowness of writes. Better to RAID1 your database and keep things like REDO logs, RBS and TEMP on other fast write devices. In this case you would use Oracle's REDO log mirroring.

Bruce...

   T T T T T T T T        Bruce Pihlamae
   I I I I I I I I        bpihlama_at_nla.gov.au
   I I I I I I I I        National Library of Australia
   T T T T T T T T        Phone: +616 262-1480
  -----------------       Fax:   +616 273-2116
 ===================

"If you swallow a live frog first thing in the morning; nothing worse will happen to either of you that day." Received on Sun Jan 21 1996 - 17:14:18 CST