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RAC & Redo logs [message #119012] Tue, 10 May 2005 05:11 Go to next message
hero
Messages: 5
Registered: May 2005
Junior Member
As far as the docs say "Each instance has its own online redo log groups which are called an instance's
thread of online redo". My question is: can I put the redo logs of a given instance to local fs ( not
visible from other nodes ) , or at least can I put one member(multiplexed copy) of the group to local fs and the other members to cluster fs or asm ?
Re: RAC & Redo logs [message #119097 is a reply to message #119012] Tue, 10 May 2005 10:07 Go to previous messageGo to next message
Frank Naude
Messages: 4570
Registered: April 1998
Senior Member
Hi,

Although each instance must have its own thread of redo, they must still reside on share storage. If a node fails, an instance on another node should be able to access these logs to perform instance recovery.

So, put your redo logs on a clustered filesystem, shared raw volumes or shared ASM disks. You can mix and match between these to your heart's content, but don't use local filsystems!

Best regards.

Frank
Re: RAC & Redo logs [message #119101 is a reply to message #119097] Tue, 10 May 2005 10:25 Go to previous messageGo to next message
hero
Messages: 5
Registered: May 2005
Junior Member
ok, but if the redos are multiplexed and only one copy
is on local file system, would there be any problem during
instance recovery ? There will be at least one copy available
for recovery.

The reason why I'm asking is: we have one dual raid array,
but in case of its failure, I need to multiplex the
redos somewhere else. buying extra shared storage for this is
expensive.

I've also tried archiving redos using LGWR flag , they're
written on local disk continuously - but what a shame, they are
not usable for DB recovery - I wonder why .

[Updated on: Tue, 10 May 2005 10:31]

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Re: RAC & Redo logs [message #119242 is a reply to message #119101] Wed, 11 May 2005 08:01 Go to previous message
Frank Naude
Messages: 4570
Registered: April 1998
Senior Member
Theoretically it sounds like it might work. However, since your setup will be pretty unique, I suggest you setup a test environment to certify your config before going life.

Best regards.

Frank
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