[DRBD-user] DRBD deadly slow
fz.lists at sis-gmbh.info
Fri Nov 21 16:09:57 CET 2008
Lars Ellenberg schrieb:
> as your controller cache has a working BBU,
> you can safely use "no-disk-flushes;"
> starting with drbd 8.2.7,
> you should then also say "no-disk-barriers;".
> verify that the settings are actually used with
> drbdsetup /dev/drbd0 show
Thanks to all for their answers. Verifiing the configuration using the
drbdsetup tool led me to recognize that the options set in the drbd.conf
file are not being inherited to the single drbd devices once set in the
global context- and so setting the paramters for each drbd- device led
to a dramatical increase in sync rate from about 3MByte/s to about
50MByte/s- BUT- this is still far below the io-performance of the
I read that the performance should be something like 10-15% lower than
the io-subsystems's performance respectively the network-performance.
I tried to raise the syncer: rate parameter but this does not change
anything. My syncer rate seems to be very constant about 50MByte/s- as I
read the syncer rate is not of interest for live write performance but
only for the resynchronisation process.
Are there any further paramters that might cap my write performance to
Thank you in advanced,
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