Posted by rojan_babes on 2012/1/12 23:18:39

Hi Centos,
I install Centos5.4 to my new server (IBMx3650M3, 24Gb memory, 2Tb Harddisk, ServeRAIDm5014, 6Gb SAS HBA), and I'm not satisfied with the duration of backup it takes 9-13 hours backing up 446GB only. I'm using tar commands and my tape drive is IBM 8765-1UX, tape-IBM LTO ULTRIUM 400GB Data Cartridge.
Is there any solution on this to make it fast backup? I'm thinking 2 hours of backup with this my specs.

Posted by pschaff on 2012/1/13 15:46:33

Welcome to the CentOS fora. Please see the recommended reading for new users linked in my signature.

No guarantee that it will help with your issue, but the first thing to do is update to (or perhaps better do a fresh install of) a supported release. The current CentOS releases are CentOS 5.7 and CentOS 6.2 - probably best for new installs, unless you have a reason to stick with the EL5 series.

Obsolete releases are not supported, nor is it advisable to be installing or running them. If you want to stick with your current CentOS-5 install then you should update with yum update to get to 5.7 as soon as possible. For a release that old, see the CentOS 5.6 Release Notes Section 4 for details on the recommended update procedure.

If more help is needed then please provide more information about your system by running "./getinfo.sh" and showing us the output file, after updating to a supported release.

Posted by TrevorH on 2012/1/13 15:49:55

Please give examples of the tar commands that you have been using. One common problem with streaming tape drives is if you do not supply the data to the drive quickly enough then it has to stop, rewind the tape, find the correct location and resume writing again. This can sometimes be fixed by supplying a blocksize to tar so that it sends enough data to the drive to keep it busy and avoid this. Also, do you have hardware compression on or off?

Posted by rojan_babes on 2012/1/13 21:34:47

Hi Phil,
Thanks for the response. I'll try to install 5.7 and inform you for the update.


Hi Trevorh,
Thanks for the response. I'm using - tar xvf file file. How to check this hardware compression?



Thanks to both of you!

Posted by TrevorH on 2012/1/13 22:36:33

To find out the status of your tape drive you can use something like



This should tell you if hardware compression is in use or not. It may also tell you the current hardware blocksize and it's also how you set both compression and blocksize in order to try to avoid the shoe shining that I suspect you are currently seeing. The 'mt' utility is part of the mt-st package so you may need to install that first. Reading `man mt` will show you a lot of options that can be set including setblk, drvbuffer, compression, defblksize, defdrvbuffer, defcompression - worth trying those one by one to see what, if anything, makes the difference.

You can also use the '-b N' switch to tar to write N*512 bytes in each block and setting this to a decent value can help a lot. Turning on hardware compression with the mt utility is also worth trying (as is turning it off if it's already on!).

Posted by rojan_babes on 2012/1/15 23:38:52

Hi TrevorH,
Guess what? When I used block on my tar backup from 9 hours daily backup it reduced to 53mins! Thank you very much!

Posted by pschaff on 2012/1/15 23:44:32

On behalf of forum contributors, you are welcome. Thanks for reporting back. Marking this thread [SOLVED] for posterity.