How to control writing to tapes in a DDS DAT drive

[Paul Singh]

Hi:

I am trying to implement the backup scheme. I got a T808-ST with six 150M DDS-4 DATs. I want to know that what is the best way to backup large file systems( ~ 10 Gb), Also, I want to control the writing to tape, ie. Just do the database backups to 1,2 DATs, do the OS backups to 3,4 DAT & use 5,6 for other(users) backups. I understand, by reading other forums that tcio is kind of obsolete & shouldn't be used for DAT's, DLT's, can you please verify that. also, is there any other commands that I can use to control the writing to tape's..Last question, would using gtar be advisable for large file systems, I know cpio & tar doesn't support large files..I started with fbackup but the problem is that I can't use norewind option with fbackup..If I can find out how to write to diff tapes at will then I can keep using fbackup, other wise I have to use some other utility..

[James Perry]

It sounds like you are having a problem I had some time back. You have an autochanger library without a changer control interface. Also it sounds like you need some media management. My suggestion, if you have the budget, is to look at a backup product. These packages will let you do what you are trying to do. Both OmniBack and Veritas, as well as others, will control the movement of tapes in the library as well as let you specify which tapes are assigned to which backups.

I know that budgets are tight everywhere, but the problem I faced was that the libraries I had did not provide a command line interface for tape movement. I was going to have to develop that code from scratch as well as a backup software package to handle switching tapes on end of media errors from tar and cpio.

[Paul Singh]

ok..Thank You for suggesting the omniback..I still have the question if I can use tcio with the DAT drive that I have?? also, can I use gtar/tar/cpio/fbackup with tcio with the tape library T808-ST with 6 150M DDS-4 DAT's..

[Leif Halvarsson_2]

Hi,
I don't realy understand why you want to use tcio, this is a very old (and obsolete from HP-HX 11.11) utility, designed for for improving performance of CS/80 (very old) tape devices when used in conjunction with cpio. If that is what you want it is better to look at the ftio utility, a kind of improved (faster) cpio.

[Dave Wherry]

I'm not understanding why you can not direct a specific backup to a specific tape drive. Each of those drive has a device file for it - /dev/rmt/0m, /dev/rmt/1m, /dev/rmt/2m...
Assign one of those drive to be your target and that's where the backup will be written.
Also, you can use the no rewind devices - /dev/rmt/0mn, etc and the tape will not rewind.

[Paul Singh]

James: I am looking into getting omniback installed. How can I manipulate tapes once I have omniback, ie. writing different backup sets to different tapes...& would using DAT drive with omniback be an issue??

Dave: There is only one drive, with 6 DDS tapes it..I dont have multiple tape drives, so when I do ioscan -fnC tape, I get /dev/rmt/0m, /dev/rmt/0mn..etc..

[Michael Tully]

Although I am not familiar with that particular unit, there should be no problem as long as you can get a tape loaded, and then the tape offloaded. OmniBack will write to virtually any DDS drive. Have a look in the device matrix -: Start from here: http://ovweb.external.hp.com/lpe/doc_serv/

Within OmniBack you can nominate each device seperately and also use the same device logically with a different name as long as the same lock name applies.

Have a look here for some information on omniback/data protector.
http://www.openview.hp.com/products/dataprotector/index.asp