Re: [BackupPC-users] Poor backup performance

[David R. <dr...@gm...>]

On 3/28/07, John T. Yocum <jo...@fl...> wrote:
> Here is the iostat output, the server is doing two full backups at the
> moment, along with a nightly. Server specs: P4 3.2Ghz, 512MB RAM, 300GB
> SATA drive.
>
> [root@backup2 ~]# iostat
> Linux 2.6.9-42.0.10.ELsmp (backup2.fluidhosting.com)    03/28/2007
>
> avg-cpu:  %user   %nice    %sys %iowait   %idle
>             2.98    0.00    0.76   50.02   46.24
>
> Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
> sda              69.48       798.71       428.68 1556126098  835203048
> sda1              0.00         0.00         0.00       1556        200
> sda2              0.17         2.68         0.57    5219723    1109536
> sda3              0.00         0.00         0.00       1073        320
> sda4              0.00         0.00         0.00          2          0
> sda5              0.23         3.04         1.14    5914146    2215408
> sda6            111.33       792.87       426.97 1544752254  831876168
>
> On that server, we're seeing backup speeds as low as .11MB/s which are
> backups of several thousand files. Some backups are over 1MB/s, but
> those are servers with only 100ish files.

Was this a raid 5 or raid 1 system with those SATA drives?

I am concerned about the fact that it's reporting 50% of it's time in
system instead of near 100% in wait which indicates some other sort of
bottleneck. If you run iostat with a 5 second interval over a few
intervals does the avg-cpu look similar?

Also do you have the dir_index option on? (check by running `tune2fs
-l /dev/sda6`) Not sure how much of a difference that makes with
backuppc loads, but that does help significantly with metadata
operations on large directories.

It also looks like you are doing tar backups, have you tried rsync backups?

-Dave