[DRBD-user] ProtocollError using on-congestion pull-ahead

Felix Frank ff at mpexnet.de
Fri Feb 8 10:08:03 CET 2013

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


Hi,

On 02/07/2013 08:58 PM, Holger Steinhaus wrote:
>         resync-rate 200M;

Uhm, what? That's more than your link can do. You want to max this at
30% of your maximum throughput, tops. Otherwise the resync may interfere
with on-line write performance.

>         al-extents 389;

Why? This should be chosen to be as large (a prime number) as possible.

Have you looked through
http://www.drbd.org/users-guide/s-throughput-tuning.html?

It can also make sense to tune the tcp buffers on OS level (i.e.
sysctl). I can't find any good docs about that ad hoc, though.

HTH,
Felix



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