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RE: help - raw disks

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Date: Tue, 12 Sep 2000 10:16:21 +0200
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Using raw devices instead of regular FS files is not so much overhead, you just have to be very rigourous.
Yes the disks slices must be owned by oracle, so that the processes can write to them : chown oracle:dba /dev/rdsk/c2t4d9s? for each disk will do that for you.
No you can't rename your slices/datafiles : what we do here, to easy datafile management, is to create a directory in /dev/rdsk named as the ORACLE_SID and create symbolic links in that dir pointing to raw slices :

in /dev/rdsk/ORCL :

SYSTEM_01 -> /dev/rdsk/c2t3d9s0

so to add a datafile to a tablespace : alter tablespace SYSTEM add datafile '/dev/rdsk/ORCL/SYSTEM_01' size 100M;

When you drop a tablespace, you do not need / cannot "drop" the raw datafile , just reuse it !

To see/change the disk partitionning, use prtvtoc/format /dev/rdsk/c2t4d9s0 ( that's on solaris ).

Do not hesitate to email me directly if you need futher assistance.

> ----------
> From: Brian Wisniewski[]
> Reply To:
> Sent: Monday, September 11, 2000 22:10
> To: Multiple recipients of list ORACLE-L
> Subject: help - raw disks
> I've never used raw devices before and could use some help. Using raw
> devices was not a decision I was involved in and not one I can change.
> I've read about as as much as I can on MetaLink and anywhere else I could
> find info. Now I could use some clarification and help.
> Solaris, Oracle 8.1.6
> Here are just 3 of the 210 partitions available
> lrwxrwxrwx 1 root root /dev/rdsk/c2t4d9s1/dev/rdsk/c2t4d9s1
> ... /dev/rdsk/c2t4d9s2
> ... /dev/rdsk/c2t4d9s3
> I am under the impression Oracle/DBA needs to be the owner and group of
> the partitions I will be using - is this correct? chown oracle
> /dev/rdsk/c2t4d9s1, chgrp dba ...
> I know there can only be 1 datafile per partition but can I name datafiles
> on these partitions just like on regular file systems?
> eg. create tablespace raw_data datafile '/dev/rdsk/c2t4d9s2/raw_data.dbf'
> size 500M or is the name of the device the file name? '/dev/rdsk/c2t4d9s2'
> size 500M
> If I can name a fi! ! le 'data.dbf' how do I delete the file if I drop a
> tablespace? Is this part of the dd command I just haven't absorbed yet?
> How do you monitor I/O activity and such to know if you have a hot spot?
> I have a map someone created showing all of the partitions, controllers,
> partition size and such but is there a command to verify the size of the
> parititions? I read you should create each file at least 2 oracle block
> sizes less than the size of the partition so I wanted to verify the exact
> size before attempting to create a file.
> Any good websites or books giving detailed info about raw devices you've
> come across would also be very beneficial.
> I'm sure I could go on and on but if you could help me get started it
> would be very much appreciated. If you respond to the list could you also
> cc as I'm more likely to receive it first from
> the cc than through the list.
> Thanks - Brian
> _____
> Do You Yah! ! oo!?
Received on Tue Sep 12 2000 - 03:16:21 CDT

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