Oracle-L: RE: raw devices

From: Sherman, Paul R. <PSherman_at_elcom.com>
Date: Tue, 13 Aug 2002 07:23:33 -0800
Message-ID: <F001.004B2CDE.20020813072333@fatcity.com>

Hello,

Some may not agree with this sentiment, but unless there is an overriding reason for your needing to switch from dictionary-based tablespaces to locally-managed, I would leave well enough alone. Our OPS started out doing many things wrong, which we straightened out as we got more sophisticated about middle tiers, various contention issues, set up better granularity for locks, etc. One thing that we decided to leave in place was the dictionary-based tablespaces. We decided that it was more effort to modify the production system than would be gained by a small reduction in contention for $UET and $FET. If we were creating a new OPS, we would use locally-managed. With respect to the raw device allocation, our UNIX guy set up the devices in /dev/vg0x, and the DBAs create links (ln -s) in /u01/oradata/DB_name to those devices. When we drop a tablespace, we break the links. For a new tablespace, we create new links. This way we have client-specific datafile names in /u01/oradata/DB_name. And we created the devices based on some growth assumptions, so DBAs do not have to chase after UNIXAdmin every month to add more raw devices.

Thank you,

Paul Sherman
DBA Elcom, Inc.
email - psherman_at_elcom.com

-----Original Message-----
Sent: Tuesday, August 13, 2002 10:19 AM
To: Multiple recipients of list ORACLE-L

You do not have to do anything on Unix. Once you drop the Tablespace the raw file (device) could be used immediately in a new TS.

Regards,

Waleed

-----Original Message-----
To: Multiple recipients of list ORACLE-L Sent: 8/13/02 9:38 AM

Hi,

Wondering if anyone can help me with this question. Basically we have a parallel server setup (solaris 2.8 oracle 8.1.7.3)and so are using raw devices. I am in the process of recreating the tablspaces to be locally managed as opposed to dictionary. My question is this: In a filesystem environment, I would drop the tablespace in oracle and rm the corresponding datafile on the unix level, and then I can go about recreating my tablespace. I know that the OS doesnt really "interact" with the raw devices as such, but, in this situation would I be able to drop the tablespace and recreate it without having to do anything on the unix level? Would that corresponding raw device just be overwritten??

Any help would be greatly appreciated

Rgds

Fawzia

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Author: Khedr, Waleed
INET: Waleed.Khedr_at_FMR.COM

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Author: Sherman, Paul R.
INET: PSherman_at_elcom.com

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