[DRBD-user] slow initial sync

Seriy seriy-y at mail.ru
Wed Apr 28 18:50:34 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.


On Wed, 2004-04-28 at 12:01, Lars Ellenberg wrote:

> maybe you want to enable this one?
> > Write Cache: Not In Use

We had some file corruption, after we disabled the cache, they went away. 
I also read the article about the write cache that it's not always good to have:
http://sr5tech.com/write_back_cache_experiments.htm


> you definetely want to use 0.6.12 !!

Will upgrade

> though this has nothing to do with the issue at hand.
> 
> you are sure the raid is not rebuilding at the same time?
> 

No, it was not.

> is the device used at the same time by any applications?
> 

Yes

> > Here is the config:
> > 
> > drbd: pre-parsed needs update, parsing /etc/drbd.conf
> > .................................
> > parsed configuration NOT written to /var/lib/drbd/drbd.conf.parsed
> > CONF=(\
> >         __hash__34 \
> >   'drbd0:protocol'               'C' \
> >   'drbd0:fsckcmd'                '/bin/true' \
> >   'drbd0:disk'                   ' --disk-size=31463302 --do-panic' \
> >   'drbd0:net'                    ' --sync-rate=100M --sync-min=100M
> 
> setting min that high is not usefull, but will add latency to all other
> processes making the box feel very slow. set to 3M or 10M.
> syncer will always sync at the highes possible throughput available
> (but not more than max of course).
> 
> > --tl-size=1024 --sync-nice=19' \
> 
> sync nice 19 while setting sync min 100M is complete nonsense.
> set to 0 or -10.
> 

I just tried to force the speed to go up with no luck, before I had the
default settings with the same slow speed.

> to find your bottleneck, which is most likely NOT drbd itself,
> you may want to check:
> 
> what results does bonnie++ (just for example. or any other benchmark utility you
> want to use) give, on a
>  - non-drbd partition on the same hardware
>  - unconnected drbd partition
>  - connected (not syncing) drbd partition
> 
> measure the performance and latency (rtt) of your network,
> especially when saturated.

Thanks, I'll try to run the tests and will repost.





More information about the drbd-user mailing list