[DRBD-user] resyncing, bandwidth limits and new writes.

Dominik Klein dk at in-telegence.net
Tue Apr 27 13:41:42 CEST 2010

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

If by limiting bandwidth you mean the "rate" configuration in the syncer
section, then that does only limit the rate for background
synchronisation. The "foreground" sync of current writes is not affected
by that setting. That always happens as fast as possible.


On 04/26/2010 04:08 PM, atp wrote:
> Luciano,
>  Thanks for the response. The io scheduler is already deadline. The
> "HDD" is a hardware raid array of 12 drives, and shows no sign of
> excessive iowait or read exhaustion. 
>  I'm more interested in write bandwidth, not read, and how that competes
> with the background replication bandwidth as a system is resyncing. 
>  The problem appears to be that writes coming into the primary are
> replicated across to the secondary, which is also resyncing. These can
> take a long time to fulfil, and I'd like to give them priority. Secondly
> does limiting the bandwidth for drbd apply just to resync writes, or to 
> all drbd traffic.
>  andy
> On Mon, 2010-04-26 at 15:58 +0200, Luciano Rocha wrote:
>> Your hdd bandwidth must be exhausted on reads. Try changing the IO scheduler to deadline.
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