[DRBD-user] drbd tranfer limitations (random and sequential acccess) using raw

Lars Ellenberg Lars.Ellenberg at linbit.com
Thu Sep 23 16:45:58 CEST 2004

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


/ 2004-09-23 10:44:47 -0300
\ crsurf:
> 
> Yes is it, when using database throughput not pass 6 Mb/s.

so running your database on top of drbd gives 6 MB/sec throughput.
resync has nothing to do with it.
right?

> > how do you measure?
> 
> I?m using iptraf to view network traffic and is that wich says the
> throughput I mencioned before (4~6 Mb when inserting in database and
> 40~50 Mb/s when doing SyncingAll).
> 
> This is the output of iostat on primary server
> 
> avg-cpu:  %user   %nice    %sys %iowait   %idle
>            0.79    0.00    1.54    3.28   94.39
> Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
> sda             120.44      5271.05      1872.72  290326040  103148100
> sda1              0.00         0.05         0.01       2928        424
> sda2            120.43      5271.00      1872.71  290323088  103147676
> 
> 
> This is the output of iostat on seconday server
> 
> avg-cpu:  %user   %nice    %sys %iowait   %idle
>            0.32    0.00    1.82    3.58   94.27
> Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
> sda             212.38      1159.70      6143.03   84933272  449898916
> sda1              0.00         0.02         0.01       1736        416
> sda2            212.38      1159.67      6143.02   84931456  449898500


this is almost completely irrelevant.

I ask you to run your database benchmark on some local device,
and on drbd, and compare the results.

and using other well established benchmarks, like
bonnie(++), tiobench ... 
might be helpful for you to find the actual bottleneck.

again, run them on some local disk,
and then on top of drbd,
and compare the results.


	Lars Ellenberg

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