Re: SAN revisited

Ok, I'm going to tell you what we did and the theory behind it. Also, I haven't read the white paper that is previously posted, but I will now.

We put the redo logs and archived redo's on the local disk. We have an IBM AIX box using ssa, and the SAN is an IBM Shark. The theory behind this is, if the Shark was writting bad cache to the redo logs, the DB couldn't be recovered. Yes, the same thing could happen on the local box. However, if the SAN was writting bad cache to the DB files and the redo logs weren't getting the bad cache writes, cause they are on the local disks. The database could be recoverd. If everything was on the SAN then the DB would be trashed for sure. You would have to pull out backups before the SAN starting writting the bad cache to disks. Basically this is making sure that there wasn't a single point of failure. Like I said that was the theory here.

So far, we haven't had any bottle necks by putting the redo logs and archived redo logs on the local SSA drives. Yes they are mirrored.

Actually, I'm going to read the white paper now to see what it says.

skapitza_at_volcanomail.com (s.kapitza) wrote in message news:<26703915.0206052247.7fc1647a_at_posting.google.com>...
> hi,
>
> i m having here a compaq san.
>
> my expirience is, that you should have at least a mirror of the
> archives (if you have one) on the local disk. So if your San is going
> to sleep, you could
> probably recover at least your database somewhere else.
>
> regards
>
> stefan kapitza
>
>
> spamdump_at_nospam.noway.nohow (Ed Stevens) wrote in message news:<3cfe711b.88492845_at_ausnews.austin.ibm.com>...
> > A few weeks ago I posted, requesting general comments and experiences on the use
> > of SAN with Oracle databases. Now I have a followup.
> >
> > Given a server connected to a SAN (this will be Dell hardware if it makes any
> > difference) and hosting multiple databases, is there any performance or
> > administrative advantage to keeping some of the files on local drives?
> >
> > What I'm thinking here is that perhaps local drive access will be somewhat
> > faster than the SAN and so might be a better location for rollbacks and temp
> > space.
Received on Thu Jun 06 2002 - 09:17:57 CDT