Re: Backup Recovery Strategy for Large Database

"P.E. Detzel" <ctg27516_at_ctg.com> wrote:

>

Where to begin. I have been struggling with backup for the better part of a year now. There are several issues:

You must have a backup system that has sufficent capacity to back up your database in the alloted time. There are several choices:

	4mm - sustaind raw datarate of 500k/sec (use HP's dds2
		devices, the others are not reliable)
	8mm - Same as above, larger capacit but less reliable
	3480/3490 - sustaind raw through put of approximately 
		2meg/sec.  The tapes are small.  No more than a 800k
		per tape.  Get a BIG jukbox.
	DLT - Sustained raw through put of 1.2meg/second.

	This covers the commercially availabel units that I have 
	been able to identify as being viable.

Even with a 3480 device it would take you 11 hours to backup your database. So, you will need to have several devices that you can drive simultaniously. You will want a software package to manage your tapes and to drive your backups. And you will need to have your tapes in one or more jukboxes because 80 gig is not going to fit on one tape or even one tape per machine, thoug you could get close with DLT or 8mm.

I my opinion, the best software package on the market for large backups is Alexandria from Spectra logic. Others to consider are Open Vision (it may not run on your equipment) and Lagato (This package is much better suited to running many small backups ).

HP uses Alexandria internally for there large backups.

What ever you buy be shure to perform a through test of both backup and recovery form the actual equipemtn you plan to use. We faild to do this and as a result we have a pice of hardware that works flawlessly, and a pice of softwar that is good. But they don't work well together. This was an expensive oops.

You can make a backup from a broken mirror. My understandig is that the database must be in archive log mode when you break the mirror. I know of one site that performs their backups in this fasion.

Good Luck.
in archive log mode when you break the mirror Received on Fri Jan 27 1995 - 07:50:34 CET