Interface, GUI and issuing commands slow during backup

Asked by Richard

Hi Guys

I need some help from someone who knows how the priority of Back In Time works.

We have a HP Quad Zeon 2.4g with hardware raid controller running Debian Squeeze. We have a mirror drive that we backup to a single drive using Back In Time. All drive are on the RAID controller and are SATA Solid State Disks.

When the backup is occurring some instance of the system slow down very badly. Example clicking on the Debian file browser gui to view system file can take up to five minutes to complete. When issuing commands such as Shutdown the server will only shut down when the backup is finished. When inserting a USB drive the usb drive will not be mounted or displayed in the GUI window.

Is their a priority setting that we can change to ensure that it dose not affect any other processes that are occurring? I note that it's nice process is already set to 19, the lowest I think?

Thank you
Richard

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Germar (germar) said :
#1

Do you have 'ionice' enabled in 'Expert Options'?
'nice' is just for processing performance. 'ionice' is for read and write performance.

Regards,
Germar

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Richard (richardxo) said :
#2

Ok you may have found the issue then. In my version of Debian Squeeze Backintime is v0.9.26-4. I just tried to upgrade to version 1.0.10-1 from the Wheezy repository but it want install/uninstall a lot of other packages. I will hunt about to see if I can find a Backintime v1.0.10 package for Squeeze.

Really appreciated your help

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Germar (germar) said :
#3

You can run backintime manually to check if ionice will solve this. Type 'ionice -c2 -n7' and add the BIT part from crontab.

It also sounds like a general IO performance problem of your system. Maybe you should investigate on your Raid controller (correct kernel module, irq conflict, etc.)

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Richard (richardxo) said :
#4

Germar

It worked great! It is much better. So glad you replied to the post.

If I change the line cron (It says not to) should that be ok?

Do you recommend ionice -c2 -n7 or ionic -c3 -n19? We would prefer the priority of the backup to be as low as possible to avoid any potential user disruption.

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Richard (richardxo) said :
#5

Would this line be correct below if I dropped it into the cron?

@hourly ionice -c3 -n7 nice -n 19 /usr/bin/backintime --backup-job >/dev/null 2>&1

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Germar (germar) said :
#6

'man ionice':
-c, --class class
      Specify the name or number of the scheduling class to use; 0 for
      none, 1 for realtime, 2 for best-effort, 3 for idle.

-n, --classdata level
      Specify the scheduling class data. This only has an effect if
      the class accepts an argument. For realtime and best-effort,
      0-7 are valid data (priority levels).

ionice -c3 -n7 is the lowest level you can set.

Be aware that BIT will override your changes in crontab. Alternative you can disable BIT's automatic and add a custom cron-job in /etc/cron.d/backintime:
0 * * * * <your_backup_user> [ -x /usr/bin/backintime ] && nice -n 19 ionice -c3 -n7 /usr/bin/backintime --backup-job >/dev/null 2>&1

Regards
Germar

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Richard (richardxo) said :
#7

German

All worked great thank you very much for your help and time.

:-)