On Sat, Dec 27, 2014 at 4:31 PM, Lindsay Mathieson
<lindsay.mathie...@gmail.com> wrote:
> On Sat, 27 Dec 2014 04:59:51 PM you wrote:
>> Power supply means bigger capex and less redundancy, as the emergency
>> procedure in case of power failure is less deterministic than with
>> controlled battery-backed cache.
>
> Yes, the whole auto shut-down procedure is rather more complex and fragile
> for a UPS than a controller cache
>
>> Anyway XFS nobarrier
>> does not bring enough performance boost to be enabled by my
>> experience.
>
> It makes a non-trivial difference on my (admittedly slow) setup, with write
> bandwidth going from 35 MB/s to 51 MB/s
>
Are you able to separate log with data in your setup and check the
difference? If your devices are working strictly under their upper
limits for bw/IOPS, separating meta and data bytes may help a lot, at
least for synchronous clients. So, depending on type of your benchmark
(sync/async/IOPS-/bandwidth-hungry) you may win something just for
crossing journal and data between disks (and increase failure domain
for a single disk as well :) ).
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