I noticed that my tape drive (HP DAT autoloader) requires a "mt compression 0" prior to tape access. It seems that even after reading the tape label in a non-compressed tape, when it writes, it uses hardware compression. I noticed it comparing the tapeer data transfer rates in several amdumps after "mt compression 0", and right after power cycling the server and the tape drive: approx 3000KB/s w/ non-compression, and approx 2500KB/s w/ compression.
I thought about running "mt compression 0" before each amdump (in a single script, via crontab), but my system rejects the mt command when no tape is loaded: $ mt compression 0 /dev/tape: Input/output error But after a "amtape ... slot current", the mt compression command runs fine. Is it possible to issue the mt command after amdump doing an amtape, but before actually dumping? Maybe I could to a "amtape ... slot current/next/?" before the amdump. What argument after "slot" shall I use to maximize the probability of amdump finding already in the slot the desired tape? Cheers, Rodrigo -- *** Rodrigo Martins de Matos Ventura <[EMAIL PROTECTED]> *** Web page: http://www.isr.ist.utl.pt/~yoda *** Teaching Assistant and PhD Student at ISR: *** Instituto de Sistemas e Robotica, Polo de Lisboa *** Instituto Superior Tecnico, Lisboa, PORTUGAL *** PGP fingerprint = 0119 AD13 9EEE 264A 3F10 31D3 89B3 C6C4 60C6 4585
