Re: Physical I/O on a SAN or NAS

rgaffuri_at_cox.net (Ryan Gaffuri) wrote in message news:<1efdad5b.0312050706.20a680c7_at_posting.google.com>...
> We are using an NAS. Are there any conventions to handling Physical
> I/O distribution on NAS or SANs? They are relatively new. Since we
> dont control which disk or mount point datafiles go on, we really
> can't spread out the I/O. Does it matter if we put tables in different
> datafiles then?
>
> any conventions or articles would be helpful.

Just think of logical volume groups (on Hitachi they call it volume group segmentation) as disk devices for OFA purposes. You do want to spread them over such devices to avoid hotspots - this works because you want to avoid contention on stripes/controllers just as you would between regular disks, although it is less deterministic (depending on how "smart" your device is). At least with SAN, I don't know about NAS. I'd say the white papers at emc.com, for example, are pretty bogus as far as oracle layout is concerned, although I'm sure there are people who would still say just use $ORACLE_HOME/dbs and let striping worry about it.

I'm sure your vendor would love for you to buy training or consulting services on how to set up your NAS. The question to ask them is "I know that I will have certain hotspots, how do I detect and chill them?"

http://www.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&th=4e511714e9a98e50&seekm=3A40C0D0.438F98EB%40edcmail.cr.usgs.gov#link11

http://www.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&th=148e5b724cea007e&rnum=3

http://www.google.com/groups?q=SANS+author:Nuno&hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=3cd68460%240%2415474%24afc38c87%40news.optusnet.com.au&rnum=7

jg

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