[DRBD-user] database on drbd
Lars.Ellenberg at linbit.com
Wed Mar 10 16:12:54 CET 2004
/ 2004-03-08 16:59:59 -0500
\ Carson Gaspar:
> >Using "B" does currently not gain anything, but degrades
> >throughput, and loses transactional semantics, so should be avoided.
> Perhaps a note to that effect can be added to the docs? We went with B here
> because if both machines went down at once, we were hosed anyway, and
> wanted better performance. *sigh* Time for another maintenance window (and
> I just upgraded everything yesterday!)
Hm. It is, is it not?
from the scripts/drbd.conf example config file:
# transfer protocol to use.
# C: write IO is reported as completed, if we know it has
# reached _both_ local and remote DISK.
# * for most cases.
# * the only protocol with true transactional semantics.
# B: write IO is reported as completed, if it has reached
# local DISK and remote buffer cache.
# * should perform better than C,
# but according to benchmarks, does not.
# so use C instead for now.
# A: write IO is reported as completed, if it has reached
# local DISK and local tcp send buffer. (see also sndbuf-size)
# * for high latency networks
protocol = C
Yes, I know in previous releases (up to ? I forgot) "B" was
recommended "for most applications".
And btw, benchmarks are just that, and if you do performance tests
yourself, this might be different for you.
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