[DRBD-user] Reducing loadavg / iowait? - A few extra questions

logch_l at wldelft.nl logch_l at wldelft.nl
Tue Aug 2 22:55:27 CEST 2005

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

>> -----------------
>> resource drbd0 {
>>     protocol               C;
> Depending on your requirements regarding the data safety you could try
> to use  protocol A or B, we are using B and are quite pleased.

Thanks for the suggestions.

about nfsd) I can't export async because we need the most gracefull
fail-over ; there are always HPC clients writing..

drbd protocol) I was wondering about using protocol B after some googling
but couldnt get someone to confirm it does reduce latency. Regarding safety,
our drbd cluster nodes never go down at exactly the same moment (the only
situation in which a drbd 'write' can get lost using proto B).

Q1: How does using B make a difference?
Q2: Can one change to protocol B on-the-fly using 'drbdadm adjust'?

drbd hot area) Currently we use 521 al-extents for a 1.4 TB device. How much
difference does it make when we increase this number? (nr of writes vs. size
of al-extents) And also can this be changed on-the-fly?

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