Re: Backup and recovery of Large databases

In <703873121wnr_at_carlc.demon.co.uk> Carl_at_carlc.demon.co.uk (Carl Churchman) writes:

>
>I am the Senior System administrator/DBA of a Sequent SE60.We
>have a large database of 40Gb which has to be highly available.
>At present we run hot backups 6 nights a week and run archiving.
>A cold backup is run on a Saturday night.These backups take about
>4 hours (not bad eh?) using 4 * 10GB (compressed) Exabyte tape drives
>and PTX/Backup. My problem is this:
> I have tried to recover the database on another machine,to test
>disaster recovery.The restore is still running and by my calculations
>is going to take about 42 hours!.How are you other DBA's backing up and
>recovering your large databases and how long do they take?
>
>Thanks
>
>
>Carl Churchman
>carl_at_carlc.demon.co.uk

In my experience, the recovery should not take nearly that long. The longest task in any recover that I have done is to find the backup tapes and recover the operating system files. The recovery itself takes very little time, depending on how many archive redo log files you have to apply.

Are you attempting to recover from your hot backup? How many archive log files do you typically have to apply? How do you actually do your hot backup?

We typically:

	Set BEGIN BACKUP on all tablespaces
	Backup the database files
	Set END BACKUP on all tablespaces
	ALTER SYSTEM SWITCH LOGFILE;
	ALTER DATABASE BACKUP CONTROLFILE TO 'archive location';
	Backup the archive log files

During a recovery we:

	Restore the database files, control files, and archived log files
	startup mount
	set autorecovery on
	recover database

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Bob Swisshelm                | swisshelm_at_Lilly.com     | 317 276 5472
Eli Lilly and Company        | Lilly Corporate Center  | Indianapolis, IN 46285