[DRBD-user] Re: drbd 0.7.21(kernel 2.6.17) hang problem

Maciej Bogucki maciej.bogucki at artegence.com
Thu Sep 21 11:12:59 CEST 2006

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


>>>in drbd:
>>>you could play with "unplug-watermark" and "max-epoch-size" (and
>>>possibly max-buffers).
>>>when I say "play", I mean it.  it could get better if you increase,
>>>it could get better when you decrease, it could get better if you
>>>adjust in opposite directions (where possible), and it could happen to
>>>have no noticable effect at all, which is all very dependent on your
>>>lower level io subsystem and on network timings and ...
>>
>>I know, than I can play with them, but there is another strange thing. When I disconnect secondary node(shutdown 
>>heartbeat, and drbd) I get lags also. Also I don't have much traffic on database(1256 writes per minute - so I's 
>>20KB per seconds, and only a few reads per minute), so playing with "net" parameters is not necessary in my case. I 
>>think that it is drbd bug or some stupid thing :)
> 
> 
> what about al-extends?
I have play with it(increase and decrease one) without positive results :(

> how often do the bm: and al: numbers increase in /proc/drbd?
> (watch -n1 cat /proc/drbd, and look at that)
They don't change often, only a few single(+1) increases per hour.

al-extends, and all "net", "syncer" directives have only sense when 
there is another node. When I only leave one node(primary) I still have 
laga. And it is strangest thing to me.
It is x86_64 HA Cluster, but I have the same hardware in another 
location and there are no problems. Strange :)




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