Monday, May 25, 2009

(dd command) Voting Disk backup 11g; Cannot be done online


I read ... to improve skills and ideas on Oracle database 11g RAC Administration presentation.

I found... many things different idea 10gR2 RAC.

About "Back Up and Recover Your Voting Disks"...
That's sure we can backup by "dd" command ("ocopy" on windows)... & the block size for the dd command should be at least 4 KB and it's recommended to use symbolic links.

When Read... more! I found something different.

On 10gR2 RAC used "Can be done online" words ;)
A backup taken via the dd command can be a hot backup, which means that the Oracle Clusterware daemons do not need to be stopped in order to take this backup.

On 11g RAC used "Cannot be done online" words ;)
Before backing up your voting disk with the dd command, make sure that you stopped Oracle Clusterware on all nodes.

I don't know yet... why? or just recommend... But one thing, after install oracle clusterware, add node or delete node...on 11g RAC.
I won't forgot to backup voting disk. Cuz, I don't want to stop all nodes ;)


4 comments:

Anonymous said...

The backup can be performed while the 11g CRS process is active, you do not need to stop crsd.bin process before taking a backup of the voting disks (About Backing Up and Recovering Voting Disk - B28252-03) :)

Surachart said...

http://download.oracle.com/docs/cd/B28359_01/rac.111/b28252/adminoc.htm#TDPRC052

thank you... for your suggestion!

it's just my curious on 11g RAC presentations (Oracle University)

A new backup of one of your available voting disks should be taken any time a new node is added, or an existing node is removed. The recommended way to do that is to use the dd command (ocopy in Windows environments). As a general rule on most platforms, including Linux and Sun, the block size for the dd command should be at least 4 KB to ensure that the backup of the voting disk gets complete blocks.
Before backing up your voting disk with the dd command, make sure that you stopped Oracle Clusterware on all nodes.
The crsctl query css votedisk command lists the voting disks currently used by CSS. This can help you to determine which voting disk to backup.
The slide shows you the procedure you can follow to back up and restore your voting disk.

Martin Berger said...

I'm just not sure what a backup of the voting disk is really good for.
All information is stored in ocr, and if the cluster crashes totally and voting disks are unavailable, I wil lrecreate them without loosing any data.
So why backup them? (What am I missing?)

Surachart said...

Sure! Voting backup can not help anyway, if OCR lost...

VOTE Disk, I backup after setup Oracle RAC completely. perhaps I forgot it where is

OCR.. oracle cluster auto backup... but I still use "ocrconfig -export" every days, because I'm afraid with it failure.

By the way, I have one OCR + one VOTE, but I never lost them with 4 years experience on RAC.
Perhaps I've used High Availability Storage;)

My idea about backup... we should backup them(OCR+VOTE) anyway. if they're crashed, we can use backup, I hope I'll use recreating(root***.sh) Oracle RAC last solution;)

;)