Linux Tape Backup
Linux Drivers
LSI SAS2008
LSI SAS 9200-8e 6Gbs PCI Express SAS Host Bus Adapter
My first obstacle was getting the drive to show up in Linux. Apparently RHEL/CentOS decided to stop putting LSI SAS2008 drivers in the distro, starting with RHEL/CentOS8. Here's some more info: https://access.redhat.com/discussions/3722151 Also a helpful vid: https://www.youtube.com/watch?v=4fOAuXiynYM
I was able to get the correct drivers for my LSI SAS2008 using the driver that matched my kernel (CentOS Stream 8/4.18.0-448.el8.x86_6) here: http://mirror.centos.org/centos/8-stream/kmods/x86_64/packages-rebuild/Packages/k/ (I used kmod-mlx4-4.18.0~448-1.el8s.x86_64.rpm).
Also, FWIW, I'm using a Quantum Ultrium LTO 4 (Model B) SAS Tape Drive attached to the LSI SAS9200-8e. I'm using a fresh install of CentOS Stream 8 on a Dell PowerEdge R730xd.
LSI SAS3008
Dell 12Gbps HBA / LSI SAS 9300-8e 12Gbs PCI Express SAS Host Bus Adapter
I have since switched to a LSI SAS3008 PCI-Express Fusion-MPT SAS-3 (branded as a Dell 0T93GD 12G SAS Low Profile Dual Port HBA) and the card just worked out of the box with RHEL 9.3 (it is using the built-in mpt3sas kernel driver). I'm still using the Quantum Ultrium LTO 4 (Model B) SAS Tape Drive, mounted in a 2U Dell PowerVault 114X enclosure (left drive in picture at top of page; the other is not connected yet).
Using The Tape Drive In Linux
The main program we will use is called mt. You can install it with sudo yum install mt-st (or equivalent command for your distro).
Device Names
The device name you utilize affects behavior after command executions:
/dev/st0- rewinds tape after being written to
/dev/nst0- don't rewind tape after being written to
More info: https://forums.fedoraforum.org/showthread.php?59746-SCSI-Tape-Drive
Main Operations
Write directory to blank tape
Make sure you are at the beginning of the tape:
mt -f /dev/nst0 rewind
Write directory to tape:
tar -C /directory/to/backup/ -cvf /dev/nst0 . | tee /home/file-listing-0.txt
You can omit the piped tee command if you don't want to save a listing of files. Not sure why you'd do that though...
Append directory to existing tape
Fast-forward to beginning of next new file:
mt -f /dev/nst0 asf <file#>
Write directory to tape, excluding files already written previously:
tar -C /mnt/hdd/os/ -cvf /dev/nst0 --exclude-from=/home/file-listing-0.txt . | tee /home/file-listing-1.txt
Restore an individual file
Fast-forward to the tar file that contains the file you want:
mt -f /dev/nst0 asf <file#>
Extract the file to the PWD:
tar xvf /dev/nst0 "filename.ext"
OR Extract the file to a specified directory:
tar xvf /dev/nst0 "filename.ext" -C \some\dir
Other Useful Operations
Check if tape is online
mt -f /dev/st0 status
A cartridge is inserted and ready to write. Because we used /dev/st0, the tape rewound itself after executing the command, and is now positioned at the beginning.
Check usage and capacity of a tape
sg_logs -a /dev/nst0 | grep -E "native\ capacity"
List The First file
file - < /dev/nst0
Example Output: blah
Forward Tape To Next File
mt -f /dev/nst0 fsf 1
Seek To A File On The Tape
mt -f /dev/nst0 asf {file_number}
File numbers start at zero (0).
Rewind The Tape
mt -f /dev/nst0 rewind
List The Files In The Current Tar File
Make sure you move to the tar file you want, first
tar tvf /dev/nst0
or, you can also write the file list to a file so you have a record of files:
tar tvf /dev/nst0 | tee {listing.txt}