What is the "sg" device?
The reason I ask, is that I have a file server running CentOS 4.2 on a Dell Precision 1650. Disks are attached via QLogic FC. I backup to a Qualstar TLS-4222 tape changer, with AIT-2 tapes, which is connected over an Adaptec 29160 Ultra 160 SCSI. The software I'm using is Legato Networker version 7.1.2. I'm backing up a bit under 1 TB a month with this.
Quite frequently these days (meaning once a month or two), the Networker software loses the ability to control the tape changer. Mount, unmount commands just don't work any more. The only way I can seem to fix it, is to use the Networker admin software to remove the robot, and tape device, and then recreate it with the Networker jbconfig command.
The jbconfig command detects the Qualstar, and then detects /dev/sg3 as the tape device. Now Networker can use this device to move tapes around in the robot, but not to read and write. So I have to delete / dev/sg3 from the Networker configuration, and then add /dev/nst0. And then it works (for a while).
So I'm wondering, why the software is setting me up with /dev/sg3 instead of /dev/nst0; and is there anything I can do about it. Bonus question if anyone else had a similar issue.
Thanks, Tony Schreiner Boston College