On Monday 17 January 2005 07:45, Peter Guhl wrote: >Hi Paul > >On Mon, 2005-01-17 at 12:38, Paul Bijnens wrote: >> But you can do just the same using dd: >> >> dd if=/dev/random of=/dev/st0 bs=32k >> >> and count how many 32Kbyte blocks get on the tape. >> Expect about 15000000000 / 32768 or about 457763 blocks. >> >> Remember, it takes about 2-3 hours to fill a tape. >> >> Multiple runs should result in an almost constant number of blocks >> (plus/minus a few hundred). > >root@:/usr/local/etc/amanda/backup> dd if=/dev/urandom of=/dev/nrsa0 > bs=32k dd: /dev/nrsa0: short write on tape device >1301+0 records in >1300+1 records out >42598476 bytes transferred in 13.372441 secs (3185542 bytes/sec) >root@:/usr/local/etc/amanda/backup> dd if=/dev/urandom of=/dev/nrsa0 >bs=32k >dd: /dev/nrsa0: short write on tape device >1756+0 records in >1755+1 records out >57507912 bytes transferred in 18.072619 secs (3182046 bytes/sec) >root@:/usr/local/etc/amanda/backup> dd if=/dev/urandom of=/dev/nrsa0 >bs=32k >dd: /dev/nrsa0: short write on tape device >127+0 records in >126+1 records out >4128840 bytes transferred in 1.362397 secs (3030570 bytes/sec) >root@:/usr/local/etc/amanda/backup> dd if=/dev/urandom of=/dev/nrsa0 >bs=32k >dd: /dev/nrsa0: short write on tape device >1935+0 records in >1934+1 records out >63373386 bytes transferred in 20.628743 secs (3072092 bytes/sec) >root@:/usr/local/etc/amanda/backup> dd if=/dev/urandom of=/dev/nrsa0 >bs=32k >dd: /dev/nrsa0: short write on tape device >354+0 records in >353+1 records out >11567158 bytes transferred in 3.702742 secs (3123944 bytes/sec) >root@:/usr/local/etc/amanda/backup> dd if=/dev/urandom of=/dev/nrsa0 >bs=32k >dd: /dev/nrsa0: short write on tape device >704+0 records in >703+1 records out >23035980 bytes transferred in 7.960560 secs (2893764 bytes/sec) > >It was a little bit faster ;-) but I guess that's mainly because > this drive isn't in a very good shape... at least those rapidly > changing numbers look a lot like that. > >Regards > Peter
Is that tape being properly rewound Peter? Most drives will fully rewind a tape before they allow it to be ejected, maybe you should eject it and look at it between each pass. Or is this a case of needing to either fix the terms or sacrific a virgin over the scsi bus? I'd go for the former since the latter are a bit hard to find these days. :-) -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) 99.32% setiathome rank, not too shabby for a WV hillbilly Yahoo.com attorneys please note, additions to this message by Gene Heskett are: Copyright 2005 by Maurice Eugene Heskett, all rights reserved.
