Re: exp and archive available.... recover table

From: Alexander Skwar <usenet_at_alexander.skwar.name>
Date: 14 Jul 2007 20:30:28 GMT
Message-ID: <pan.2007.07.14.20.32.14@pan.message-center.info>

· Frank van Bortel <frank.van.bortel_at_gmail.com>:
> Alexander Skwar wrote:

>> Yes. Backup of "/" incl. subdirs (sorta. Certain directories, like
>> /tmp or /dev, are not part of the backup).
>> 
>> Alexander Skwar

>
> OK, got the picture - you basically shutdown everything, and
> make a file level copy of (about) everything. That's OK.
>
> Now, back to the basic question: how to do this, making sure
> downtime is minimized?
>
> Sorry, but here comes RMAN:
> - - RMAN can take Oracle down for you, and make a backup.
> - - RMAN runs parallel processes, speeding up the process of
> safekeeping your data (getting anxious to use the word backup :) )
> true for readers, as well as writers.
> - - RMAN stores what is needed - an empty 1TB datafile is backed up
> in a matter of seconds - it's empty. RMAN knows, your file system
> copy (or tar, or dd) does not.

All very convincing. Speed of backup (ie. writing to tape) is of no matter at all to me, with my current backup setup. Reason: I take the backup not of the original filesystem, but of a ZFS snapshot of it. Positive thing about this is, that the backup can take as long as it wants/needs, as backup time only affects how long the snapshot exists. And I do have enough free space on the zpool to cover the needed space for COW, which is required by the ZFS snapshot.

What I will probably do is:

Make app inaccessible - thx to whoever suggested this
Take vault snapshot
Start RMAN backup 4a) Make app accessible 4b) Make backup to tape and remove snapshot when done

> I'd consider RMAN,

I seriously DO consider RMAN. Not simply for the sake of parallelism, that's of course also a highly valid point, but I think I might somehow get that with putting the tablespaces into backup mode as well; no, I do consider RMAN because it does allow me to control Veritas/Symantec NetBackup as well (well, right now, my RMAN setup does not allow that, but that's just a matter of configuration, I suppose). No, what makes me consider RMAN is also, that it seems to be easier to, compared to, what does Oracle call it? "User managed backup"?, anyway, compared to putting tablespaces into backup mode.

> just for the sake of parallelism - the only
> way I can think of right now to speed up you backup procedure.

As said before - the *total* speed of the backup procedure doesn't matter. I am currently backing up snapshots. A full backup takes like 8 hours, or so (not much, I know). But I certainly want to continue taking backups of snapshots, as this seems to be a good idea. Unless someone can tell me, why this might be a bad idea.

> Hals und Beinbruch!

:_)

Alexander Skwar

-- 
Have a nice day!

Received on Sat Jul 14 2007 - 15:30:28 CDT