Re: Archiving to Tape

From: Phil Herring <revdoc_at_uow.edu.au>
Date: 1997/08/20
Message-ID: <5tftng$2ah$1@wyrm.its.uow.edu.au>#1/1

In article <19970820205700.QAA00157_at_ladder01.news.aol.com> SatarNag, satarnag_at_aol.com writes:
>Thanks for the advice, However...we run a 24/7 shop, and have very
>little/none disk drive space. It is under the "advise" of my boss, to
>archive to tape...not to disk. That way, if we experience a disk crash, we
>can recover to the last minute/checkpoint. He has informed me that we
>cannot afford to lose a day's data.

This isn't a sound argument. After all, just because you're archiving to tape *doesn't* mean that you have a good archive copy, and it will slow your RDBMS down a lot. If you must have your archives on tape, it would be better to archive to disk, then dump the log files to tape shortly thereafter via a cron job (or whatever). Or better still, stop mucking around and mirror the archive disk.

The other thing that your boss is missing is that recovering your logs from tape will take longer than taking them off disk, which slows down your recovery time significantly. This is one of those situations where somebody hasn't done their sums - ask your boss how much it will cost the business if recovery takes 40 minutes rather than 20 minutes (or whatever the figures will be for your system), and compare that to the cost of a disk to keep the last 24 hours' redo logs available. The cost of the disk is usually negligible in this situation.

Received on Wed Aug 20 1997 - 00:00:00 CDT