Re: Oracle Raw Partitions

G.Anbazhagan wrote in message <01bdd1bd$0aea6700$a29e15a5_at_default>...
>Hi ,
>There will be no performance improvement . There will be performance
>degradation.

Of course, two caches with same speed but one small ( UNIX file system buffer cache ) and one bigger or usually much bigger ( ORACLE SGA ) are better than using single big cache - SGA. Let me guess - three caches would do the job even better ?

>When you use raw partion ,Oracle writes to the device
>directly. If you use file system , it is beffered. The advantage is , when
>power fails , you are sure the data is in the disk. Raw partition only
>provides better recoverabilty.

When commit succeeds, you are sure that the data are written to disk in any case. Otherwise, when starting ORACLE again, uncommitted data would be rolled back. It doesnt depend on type of file system you are using.

>
>Backup is a real pain. You have to use dd ( dump ) . You cannot use file
>system level copying.

Quite obviously:

dd if=/dev/rdsk/c0b0t1d0s1 of=/dev/rmt/ctape1

is real pain compared with

tar -xvf /dev/rmt/ctape1 /usr/oracle/files/system1.dbf

or

ls -1 /usr/oracle/files/*dbf | cpio -ovcBO /dev/rmt/ctape1.

>Raw partition is not worth trying...
>
>regards
>anbu
>

I agree. Unless you really know something about them.

Have a nice day ! Received on Fri Aug 28 1998 - 05:19:59 CDT