[DRBD-user] Sudden high CPU load [SOLVED]

Felix Frank ff at mpexnet.de
Thu May 19 09:38:17 CEST 2011

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


On 05/18/2011 10:02 PM, Richard Stockton wrote:
>> Is NFS mounted sync or async?
> 
> NFS is mounted "sync" (NFS3 default, I believe).

This is very bad. Do use async, it's not as asynchronous as the name
implies (except if you run applications that rely on written data being
available on all nodes before the writer has closed the file).

>> Which I/O scheduler is in use for your DRBDs (i.e., for their backing
>> devices)?
> 
> cfg (also the default, I believe)

CFQ is, unfortunately, been the default for some time.

You should use noop or deadline, whatever suits your workload better.

I suggest to just go for noop on the spot. It doesn't usually hurt and
can be done on-the-fly.

HTH,
Felix



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