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

Holger Steinhaus hsteinhaus at gmx.de
Fri Feb 8 10:41:19 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.

>>          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.

Sorry, remainders of some experiments to overcome the trouble (idea was 
to de-limit synchronization bandwith and to limit the number of hot 
extents). I just return them to their defaults (removed assignmend) and 
tried again - same result. In a second experment, I limited the resync 
to 20M and increased the al extends to 3389 as stated in the doc. There 
is absolutely no change in behavior - still lots of ProtocolErrors.

I have almost forgotten the tuning approach for now - I am much more 
scared about stability and data integrity due to the obvious protocol 


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