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Doing more with Tape Drives
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- Written by angusf
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Someone gave me a DLT 7000 Sun Tape Drive. What a great thing it is even if its out of date these days. From eBay I sourced an OEM Sun SCSI cable, which I connected to an old Sun SCSI card I had lying about (like you do). I also bought a bag of unused DLTtape IV tapes and a DLT IV cleaning tape - Not cheap not dear overall.
After a reconfiguration boot -r It shows up as /dev/rmt/1u on my Solaris 10 equipped Ultra 10. Actually there are a number of devices but this one puts it in its best mode ‘maximum storage using compression’ in this drives case thats 70GB using a type IV DLT tape. I found a Sun manual for an almost identical drive at http:/dlc.sun.com/pdf/805-0648-10/805-0648-10.pdf
Now I have an Ultra 10 with a network addressable tape drive and lovely Sun documentation. My world is complete.
Well almost.
You see, tapes and tape drive technology is one of those arcane corners where my knowledge is blurred. I used to love them, but haven’t really used them in anger for years. There are loads of Unix command lines I know and love, but I do not know them off by heart enough to trust myself with them. So here's what I did: -
First things first
Set the TAPE environment variable, I set it in /etc/profile using:
TAPE=/dev/rmt/1u; export TAPE
Second things second
Check the drive
mt -f status
I get a sense key attention - I google and it turns out it just means a tape has been inserted. I run the command again and get nothing untoward.
Third things third
Backup my Ultra 10. That will be a good thing to do. The ufsdump copies a file system from a disk to a tape. It is specifically designed to be a backup utility. It supports multiple volumes and incremental backups. Sounds ideal. Its command line too. Marvellous
sync
sync
sync
init 0
Bring the system down, three syncs, old habits die hard.
boot -s
Bring the system to single user
ufsdump 0uf /dev/rmt/1u /dev/rdsk/c0t0d0s0
0 - copies the entire file system to the dump file
u - updates the dump record in /etc/dumpdates
f - specific the drive doesnt seem to use the TAPE variable..
/dev/rmt/1u - 70GB DLT IV
/dev/rdsk/c0t0d0s0 - The raw Solaris File System from my Ultra 10
So thats it. Im running it. It says my drive contains about 60GB of data so it should fit on a 70GB tape! Its says also that it will take 4.37 hours. Thats a long time. No wonder tape drives are getting out of fashion. Nevertheless I like the belt and braces approach of more than one style of backup and this is well worth the effort for me to have a library of tapes to feel good about if all else fails. I wonder how I can test it...