Re: Compression with ontape

In article <3517B655.CE63B0AD@cork.cig.mot.com>, Peter Wotherspoon <wothersp@cork.cig.mot.com> writes >Gabriela, > > >Hi. > >I've always used compressed tape devices for Informix archiving, and I've not >had any problems. If you have fewer metres of tape used up, I think you >probably decrease the risk of getting a dropout on the tape, so you make the >backup more secure, not less. It's also faster than not using compression. > >The only tricky thing is to accurately predict what level of compression you >will achieve, so that you can set the tape parameters optimally. > >From my experience, DAT tapes are more reliable than EXABYTE, but if you >replace the media regularly, everything should be OK. > Informix didn't use to like supporting compressed devices. On compressed tape drives the compression is usually implemented in software (or microcode) on the tape drive. Some of the early compression routines were buggy!! > >Peter Wotherspoon > > > >Gabriela Bellani wrote: > >> Hi, >> We are experiencing with a new tape device (EXABYTE 8500 8mmm Helical >> Scan ) for doing ontape. The default mode of operation of the device is >> with compression ON. We did a Level 0 archive (18GB to back up) with >> ontape in an hour and a half, and the corresponding restore took the same >> time... >> Are there any disadvantages when using compression ? I've heard some time >> ago that we shouldn't use compression with ontape...is that true ? >> >> TIA >> Gabriela Bellani > > > > > -- David Williams Maintainer of the Informix FAQ Primary site (Beta Version) http://www.smooth1.demon.co.uk Official site http://www.iiug.org/techinfo/faq/faq_top.html I see you standin', Standin' on your own, It's such a lonely place for you, For you to be If you need a shoulder, Or if you need a friend, I'll be here standing, Until the bitter end... So don't chastise me Or think I, I mean you harm... All I ever wanted Was for you To know that I care