Re: What should TAPESIZE be set to on a DDS2 tape drive?

It depends on how compressible your data is. The amount of data written will depend on the number of pages used rather than the size of the tape. You could try experimenting with smaller tapes to try to find out what capacity the tape actually takes. HP used to supply a utility called monitor which amongst many other things allowed you to observe how much data had been written to the various files a given process had open. In the bad old days of archiving onto 9 or 10 9 track tapes I used to use that to check for the imminence of tape changes. I don't think it's available on 10. You could try pressing HP on this, however; it wasn't available at HP-UX 8 either but when pressed they sent us a library which read from /dev/kmem and enabled us to put together a utility to check for ourselves. If you had such a tool available you could try a level 0 to a shorter tape (but still declared at 8G) and find out how much had been written when the tape ran out. That might give you some measure of compression ratio - but then different parts of you data might compress differently. Ian Scott Anderson wrote: > > The Drive is on a HP K200 running HPUX 10.0,the drive is a C1533a > DDS2 drive and is capable of 8 Gb compressed. There is some > question as to whether we can truly get 7-8 Gb of data on one 120 > meter tape or if we should just stick to the 4Gb that the tape > can hold uncompressed. I would be interested to hear from Sysadmin's > and DBA's that have used drives like I described and have restored > successfully from them. Currently we have TAPESIZE set to 7900000 > Kbytes, but some questions have been raised as to whether that amount > of data is being written to the drive. Our dbspace is approx. 8Gb. > -- > _______________________________________________________________________________ > Scott D Anderson "Don't tell me I'm burning the > Arent Fox Kintner Plotkin & Kahn candle at both ends-- > Unix System Administrator tell me where to get more wax!!" > Work (202) 857 6078 Fax (202) 775 5739 > E-mail sda@arentfox.com, andersos@arentfox.com, sander@infinite.loop.org > http://www.arentfox.com/home.html Internic SA1057