Backup Question 2

[cyoung]

I have installed a tape drive on a RedHat 8 server, and I am having problems with backing up multiple directories.

I want to be able to backup these directories without overwriting the previous set.

I am using tar in a script and calling it with cron, but if there is a better way, I would appreciate the info

Thanks!

 

[KenCunningham]

You need to specify the 'no-rewind' version of your tape for each save, this will usually be found in the /dev or /dev/rmt directories and probably end with n, for example in Solaris the no-rewind device is usually /dev/rmt/0cn.

Basically, this leaves the tape at the end of the save without rewinding it, the latter being the default behaviour. HTH.

 

[Morsing]

Use the device /dev/nst0

Cheers

Henrik Morsing
Certified AIX 4.3 Systems Administration
& p690 Technical Support

 

[KenCunningham]

Apologies - never used Linux, so didn't appreciate that the n would come at the beginning of the device name. Isn't standardisation wonderful!

 

[cyoung]

Thanks all for the replies.

So, if I understand this, I would adjust my scripts to do the following:

1. Rewind the tape when the script starts,
2. tar each directory by using the /dev/nst0
3. verifiy the backups


Thanks agian for the help

 

[KenCunningham]

Sounds about right. Be aware that verifying your backups can take an inordinate time. Possibly worthwhile if you have a test environment on which to do the verification, but an overhead on a live system. I assume you're aware of how to position the tape so that consecutive saves can be read?

 

[BobMCT]

Have you considered using "find" to create a list of files (fully qualified) to be used as tar's input stream? That way you wouldn't have to contend with the tape rewind/norewind issue and the entire operation would most likely be must faster. Here's an example:

find /usr/local/directory1 -print >tarlist
find /usr/opt/directory2 -print >>tarlist
find /etc/httpd -print >>tarlist

tar -cf/dev/st0 $(cat tarlist)

Try it - you might like it?

Bob

 

[clonny2]

If you don't intend to overwrite your previous data, then do not rewind in your script.

"1. Rewind the tape when the script starts,"


>---------------------------------------Lawrence Feldman
SR. QA. Engineer SNAP Appliance
lfeldman@snapappliance.com

 

[cyoung]

I have 7 tapes that I intend to use in a rotate scheme, so I will need to rewind.

I will try the find > cat option, as that make a lot more sense, and would make restores a lot easier.

Thanks all for the great tips and ideas

 

[cyoung]

Bob,

I am testing your idea, but getting an error stating that the argument list is too long. Any ideas on how to work around this?

Thanks

 

[cyoung]

Answered my own question (amazing what man can do.....)

tar -cf /dev/st0 -T /tmp/tarlist

Thanks again for all the tips!