User manual QUANTUM DLT1LINUX

[. . . ] The guidelines provided here should apply - with only minor changes required, if any - to your favorite Linux distribution. You need a SCSI adapter on the host If there are existing SCSI disk drives, SCSI CD-ROM or SCSI tape drives configured on your host, then you already have a SCSI adapter (or built-in interface). After shutting down Linux and powering the machine off, cable the DLTtape drive to the SCSI adapter. Most of the popular SCSI adapters provide a configuration utility that can be invoked during system powerup and BIOS scan. Such utilities are handy for verifying that the cabling is good, the host adapter sees the tape drive, and there are no bus ID conflicts. You need the Linux driver for your SCSI adapter If you've been using other devices on your SCSI adapter under Linux, you have this driver already. [. . . ] Numbering is based primarily on SCSI bus number (if you have several SCSI adapters) and secondarily on SCSI ID within a bus. A file-close on /dev/sti causes the tape drive to automatically rewind the cartridge. For example, after a tar cf on /dev/st0, the drive head will be positioned at beginning of tape. A subsequent tar cf on the same device will overwrite the previous archive. It can be used to create several archives, one after the other, on a single DLTtape cartridge. You can then select a particular archive to restore using the fsf and bsf operations provided by the mt command. This will let you locate a particular archive by seeking to the correct filemark using high-speed locate. crw-rw---- 1 root tape 9, 128 Sep 22 15:33 /dev/nst0 crw-rw---- 1 root tape 9, 129 Sep 22 15:33 /dev/nst1 crw-rw---- 1 root tape 9, 0 Sep 22 15:33 /dev/st0 crw-rw---- 1 root tape 9, 1 Sep 22 15:33 /dev/st1 If you don't see these files on your system, you'll have to build them using the MAKEDEV script, which is also usually found in /dev and can be set up using the following command construct: # . /MAKEDEV st This will typically make the device-special files for up to eight SCSI tape drives, st0 through st7. On some Linux distributions, you have to run MAKEDEV once for each drive, as in the following example: # . /MAKEDEV st0 You need the mt utility On Linux, mt is an indispensable utility when working with DLTtape drives. If you don't have it already on your system, install the mt package from your Linux distribution. GNU mt is another flavor that ships with Debian; there are probably others. GNU mt responds to a version inquiry in the following: # mt --version GNU mt version 2. 4. 2 For mt-st, the version inquiry has the following response: # mt -v mt-st v. 0. 5b We find that either mt flavor is adequate for performing basic operations on DLTtape drives. The first thing you should do after installing mt is to read the manpage. It provides a vast assortment of useful commands that are too numerous to list here. Testing your DLTtape drive If you've come this far, it's time to test that your newly-installed DLT tape drive responds properly to some basic commands. Perform an inquiry on the drive: # mt -f /dev/st0 status drive type = Generic SCSI-2 tape drive status = 1090519040 sense key error = 0 residue count = 0 file number = 0 block number = 0 Tape block size 0 bytes. Soft error count since last status=0 General status bits on (41010000): BOT ONLINE IM_REP_EN You won't see the BOT keyword in the last line unless there's a cartridge in the drive. Tar a file to the cartridge, and attempt to restore it: # cd / # tar cvf /dev/st0 tmp # tar xvf /dev/st0 tmp Until you're sure your DLTtape drive is operating correctly, use test files that you can afford to lose when you overwrite them with a restore. [. . . ] Any time you rebuild the kernel from sources, you can also hard-code the buffer-size by editing the st_options. h file (it's in /usr/src/linux/drivers/scsi). Look for the ST_BUFFER_BLOCKS parameter in this file, and change its value to 128 (the default value is 32 Kbytes). Explicitly specify a blocksize of 64 Kbyte or 128 Kbyte to backup and restore utilities such as tar: # cd / # tar cvbf 128 /dev/st0 home # tar xvbf 128 /dev/st0 home For good backup speed, you also need to make sure your disk drives and filesystems are cooperating by delivering the data fast enough. If you have several slow disk drives, experiment with software packages such as raidtools to see if disk striping helps. [. . . ]