Re: Backup Devices

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