On Tue, Nov 15, 2005 at 02:50:17PM +0000, Rodrigo Ventura wrote: > > What exactlty means the "sleep" configuration parameter in the > changer.conf file? I notice some lag in the tape commands (it seems > the tape is doing nothing, and the amtape is just sleeping...), so > maybe the default value of 90 is too conservative for my system. How > can I safely tune it?
Honestly, the only way is reduce it and see if it causes problems. If I were to try and "measure" what might be needed, I'd position a tape about 'half unwound' (fun to try and figure that out on serpentine tape formats :) Then I'd type in a rewind with mt, and while it was rewinding, but before you get a shell prompt, enter another tape command, say a dd for a gigabyte to /dev/null. But don't hit the enter key on the dd command until you see the prompt return from the mt command. Probably when the prompt appears, the tape will actually still be rewinding. However, immediately upon seeing the prompt hit the return key and notice how long it takes the tape to begin moving forward. Some drivers would give an error to status requests during this period between the apparent command completion and the actual "drive ready" condition. This is the delay for which chg-scsi is trying to accomodate. If dd receives an error, keep repeating the dd command until it does work. As a fudge factor, I'd double your measured delay. -- Jon H. LaBadie [EMAIL PROTECTED] JG Computing 4455 Province Line Road (609) 252-0159 Princeton, NJ 08540-4322 (609) 683-7220 (fax)