Re: Backup Devices

}>From ilist@rmy.emory.edu Mon Jul 28 16:39:30 1997 }>Received: from rmy.rmy.emory.edu (rmy.rmy.emory.edu [170.140.97.4]) }> by hobbes.dbintellect.com (8.8.6/8.8.6) with ESMTP id QAA28674 }> for <settler@dbintellect.com>; Mon, 28 Jul 1997 16:39:29 -0600 (MDT) }>Received: (from ilist@localhost) by rmy.rmy.emory.edu (8.7.1/8.7.1) id QAA07758 for informix-list-out; Mon, 28 Jul 1997 16:40:01 -0400 (EDT) }>From: Paul Watson <paul@wfsoftware.co.uk> }>Message-Id: <33DC7B7D.5225@wfsoftware.co.uk> }>Subject: Re: Backup Devices }>Date: Mon, 28 Jul 1997 10:59:09 GMT }>Reply-To: paul@wfsoftware.co.uk }>Organization: NCR Corporation, Waterloo, ONTARIO, Canada. }>Sender: informix-list-owner@rmy.emory.edu }>To: informix-list@rmy.emory.edu }>X-Informix-List-Id: <news.40943> }> }>Croft, Evelyn wrote: }>> }>> To: informix-list@rmy.emory.edu }>> }>> ~E~ We have the same informix backup problem. The level-0 backup }>> goes 10-12 hours (9 tapes, 4mm). We are looking into the HP Desktop = }>> DLT4000 Tape Drive. It can been seen at this location: }>> }>> http://hpcc920.external.hp.com/gsy/hardware/dlt4000.html }>> }>> I was told this would change our backup to one tape and down to }>> two hours. }>> }>> Eve }>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D }>> }>> JMDooney (jmdooney@tasc.com) wrote: }>> > I'm running Informix OnLine 5.05 on an HP E45 Server, hp-ux 9.04. My }>> > database is only 40GB, but the level 0 Informix backups are taking = }>> over15 hours to complete using the HP 4mm DAT drive . Can someone = }>> recommend a tape device they are using that can improve my backup = }>> performance. }>> }>> > Thanks }>> > JMDooney }>> > jmdooney@tasc.com }>> The HP 4mm DAT (DDS2) has a native transfer rate of 24 Mb/min which }>> to me implies that theoretical max speed for 40Gb means that it will = }>> still take 28 hrs but since it compresses, you do it in 15 hrs. }>> }>> If you convert to a DDS3, that should halve your time as it has a }>> native/compressed transfer rate of 60/120 Mb/bin and you get to stay with = }>> HP's products. }>> }>> The exabyte 8mm Mammoth would be up to 3 times as fast as the DDS3 which = }>> means that your 15 hrs could become as short as 2.5 hrs. }>> }>> And with a DLT7000 (Quantum), it will be about 1.5 hrs or less. }>> }>> The final question is ... How much is it worth to you? }>> }>> - Victor Tan }> }>I've just completed a tape storage investigation with what appeared to }>be surprising results, at least initially. Using a DLT7000 instead of a }>8mm DAT I got performance figures significantly slower than the old 1/4" }>tapes. The reason, althought Unix recognised the drive and could write }>to it there where no 'proper' device drivers. So a DLT4000 was tried }>next, complete with the correct drivers. The timing was better but only }>the same as 8mm DAT. The poor performance was due to the base machine, }>ie an 486/66. }> }>The moral. It might well be quicker than the existing hardware but on a }>poor base spec machine it makes not alot of difference. }> }> }>-- }>Paul Watson }>WF Software Ltd. }>Tel: +44 121 440 3179 }>Fax: +44 121 440 3806 }>Email: paulw@wfsoftware.co.uk }> We are backing up approximately 200 gigabytes to two IBM MagStar tape drives, and a level 0 archive via two On-Archive jobs takes around 16 hours. I believe the problem with all of these examples is that the tape drives are not being used to their maximum efficiency, since On-Archive is too slow to get them streaming. I have evaluated a few storage management products (NetWorker and Alexandria), and they are much quicker. They achieve performance improvements by executing multiple backup requests (of different dbspaces) and multi-plexing the data streams, so that the tape drives are writing at somewhere around 10-12 Mbytes/second. ------------------------------------------------------------------- Jeff Craig | dbINTELLECT Technologies, Inc. Senior Consultant | Golden, CO | (303) 275-6954 ext. 8008 | email: settler@dbintellect.com | fax: (303) 275-2134 -------------------------------------------------------------------