On Thursday 19 June 2003 14:19, Tom Brown wrote: >> Many drives have an led tally on the front to indicate when the >> comnpressor is active. >> >> And no, amanda will not use it, and in fact cannot because once a >> lock on the drive is obtained, its not released until done. >> Turning it off is best done via the dip switch or jumper settings >> programming of the drive. >> >> However, be aware that a tape written to with it on, will override >> the drives settings until such time as a block 1 write is forced >> and flushed to the media with the compression turned off. And >> drives even vary in that behaviour from production runto >> production run. I now have in service some tapes that were >> originally compressed, and a slightly earlier version of the >> ctl-96 Seagate drive than the one I started with, and even though >> the tape labels have been re-written with compression off, the led >> is on *until* a real data write starts. Those tapes didn't show >> that little foible until I had to replace the drive with a near >> identical one. > >so if i turn off hardware compression but do not relabel my tapes > amanda will still think they are being written to using hardware > aswell as software compression until i relabel them? > On DAT tapes here, even a relabel would not defeat the header flags on the tape.
Basicly, I have to rewind the tape, use dd to extract the label block, rewind the tape, turn the compression and the defcompression off, then re-write the label block with dd and flush that from the buffer to the tape with another rewind. Some tapes seems to be double stubborn and I had to do the flush with a write of about 10,000 blocks of /dev/zero. Those seem to leave the label block compressed, but the tape itself is written raw. But then DAT's can be odd critters. >doesn't sound right and i think i'm mistaken but thought i'd better > clarify. > >Tom This has been my experience. That, and a buck will get you a cuppa coffee most places. :) -- Cheers, Gene AMD [EMAIL PROTECTED] 320M [EMAIL PROTECTED] 512M 99.26% setiathome rank, not too shabby for a WV hillbilly Yahoo.com attornies please note, additions to this message by Gene Heskett are: Copyright 2003 by Maurice Eugene Heskett, all rights reserved.
