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Re: Raw Vs. File systems, your opinion?

From: Oliver Artelt <>
Date: Thu, 7 Dec 2000 02:46:15 +0100
Message-Id: <>


You can use dd oder rman to make a backup of your datafiles. Cut your disks in several partitions of the same size so you can easily add a empty partition to your tablespace or move datafiles with dd around.


On Wednesday 06 December 2000 11:43, wrote:
> Mark,
> we are considering to move from FS on raw devices. It is a misson critical
> database (8.1.7 on AIX).
> We migrated from 8.1.5 because we noticed a memory leak. Oracle told us it
> is a bug, and that we should go to the 8.1.7.
> Well, we are not sure that this resolves our problem so this is the one of
> the reason to change to the raw devices.
> What do you think? Do you have any suggestions?
> Which software are you using for backup?
> Are there OEM for raw devices?
> How do you extend your tablespaces (when I add datafile in FS)?
> TIA,
> Sonja
> -----Original Message-----
> Sent: Wednesday, December 06, 2000 1:25 AM
> To: Multiple recipients of list ORACLE-L
> Hmmm dont you love a good religious war every now and again.
> Having administered about six oracle parallel server clusters for over a
> year now, Ive changed my opinion completely on raw devices - now I prefer
> them.
> It is easier to see file and volume layouts for databases with complex
> layouts using Veritas Volume manager's (very nifty) gui. I also get
> considerable peace of mind knowing that there are no database files that
> can be deleted at the filesystem level : in the past I've had several unix
> administrators screwing up my databases by overmounting a filesystem, or
> something similar.
> No such problems with raw partitions : you are less likely to get
> accidental or malicious damage to a critical database if it is raw, imho.
> Backups are more complex, but generally only larger sites consider raw
> partitions, and subsequently have purchased an enterprise level backup tool
> that handles raw partitions as easily as files.
> An aside : for sites that use dedicated redo disks, and put two or three
> redo log files on each dedicated disk pair : is there any reason not to
> create more redo groups (say 10) on the same two disk pairs, so that online
> recovery, if it is required, is less likely to need archive logs to be
> pulled from tape? It is a better use of the redo pairs than having an
> online archive log bucket filesystem. Since redo log files are not
> hot-backedup their total size doesnt matter. Comments?
> Regards
> Mark
> Perth, Australia
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Oliver Artelt, System- und Datenbankadministration
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Received on Wed Dec 06 2000 - 19:46:15 CST

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