topic Re: Reduce fbackup time in Operating System - HP-UX

Reduce fbackup time

accent — Thu, 04 Nov 2004 05:48:18 GMT

Hi
I have one N4000 with HP/UX 11.00. I want to make a backup using fbackup command but I see that fbackup write 3 Mb each second. If I want to save 300 Gb I will spend around 27 hours.
Some tools like Legato Networker or Veritas NetBackup write 30 Mb each second.

How can I increase my fbackup performance to increase the velocity?

Thanks in advance.

Re: Reduce fbackup time

Robert-Jan Goossens_1 — Thu, 04 Nov 2004 05:55:00 GMT

Hi,

Check this doc for a fbackup -c config file example.

Document description: How to improve fbackup performance with Ultrium drives
Document id: UBACKKBRC00010991

http://www4.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000073094866

Best regards,
Robert-Jan

Re: Reduce fbackup time

D Anderton — Fri, 05 Nov 2004 08:59:59 GMT

Typically a filesystem with many small files will take a long time to backup. Try to split out your OS filesystems and data/application into seperate backups. I have seen fbackup, legato, omniback etc..etc.. all run at a few 100k/second with fileystems that contain small files. With a combination of large files and a correct fbackup config file you should get your drive running at its optimal speed. You need to be able to push enough data at the drive to keep it streaming or you get what is know as the shoe-shining (stop start) effect on the tape media.

Re: Reduce fbackup time

Ivajlo Yanakiev — Fri, 05 Nov 2004 11:11:53 GMT

Hi,

There is Patch for that. Use last patch bundle. Also find max speed for your tape.
Change your tape with new one better LTO
device. Look for disk activity when you make backup. Try to find last FW for your SCSI CTL and Tape.
Test tape performance using DD command

#### use blank tape (new one) #######
time dd if=/dev/null of=/dev/rmt/XXX bs=1024k count=100

where XXX is your tape device file.

Try tar and compare backup time !
Use fbackup for same backup and compare.
What model is your TAPE ?

Re: Reduce fbackup time

Bill Hassell — Fri, 05 Nov 2004 19:12:07 GMT

Actually, Legato, Veritas, even OmniBack (DataProtector) will run VERY slow depending on the data and the tape drive. New tape drives have become extremely fast and are pushing the limits of filesystem performance. Notice I didn't say disk performance because most disks can transfer data streams much faster than the tape drive but you may be backing up millions of files and every single file must be opened (causing a directory seek) read and closed. The only way to get past this bottleneck is to add more reader processes or backup raw disks.

For fbackup, the default is for very old, very obsolete reel-to-reel tape drives. To override the defaults, you must create a config file and put new values in it for fbackup to use:

blocksperrecord 512
records 64
checkpointfreq 1024
readerprocesses 6
maxretries 5
retrylimit 5000000
maxvoluses 200
filesperfsm 2000

Save this as something like /etc/fbackup.config and then add it to your backup command line:

fbackup ... -c /etc/fbackup.config ...

This starts the maximum 6 reader processes, reduces the number of setmarks and checkpoints, and specifies a large blocksize. This should improve the backup speed significantly. (all this assumes that the tape drive is local to your computer and not over the network)

Re: Reduce fbackup time

accent — Wed, 10 Nov 2004 03:17:34 GMT

Hi.
Thanks Bill I used the following config file (as you said me) and my backup was more fasters than the previous execution.

blocksperrecord 512
records 64
checkpointfreq 128
readerprocesses 6
maxretries 5
retrylimit 5000000
maxvoluses 100
filesperfsm 500

Thanks.