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

atp Andrew.Phillips at lmax.com
Mon Apr 26 16:08:55 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.


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.
Andrew Phillips
Head of Systems

www.lmax.com 

Office: +44 203 1922509
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