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Re: Severe netbsd-6 NFS server-side performance issues

On Mon, Jun 04, 2012 at 10:21:31PM +0200, Hauke Fath wrote:
> >
> >The adapter does show optimal battery status and write-back cache mode?
> See above. The controller setup agrees, and is happy with the battery,
> contradicting
> # amrctl stat -b
> Battery status          pack missing, charge unknown

So our driver thinks there's no battery.  You might want to double check
it isn't causing full cache flushes under the covers in that case, or
changing the array to write-through mode without telling amrct about it,
or... you get the idea.

I would say the most likely thing, if you had the same OS on the box and
suddenly started having a performance problem, is that the firmware or
driver suddenly started thinking the battery's bad -- it might be, after
all, and the setup utility might be wrong -- and converted you to
write-through mode.

Are you using WAPBL?  It would make the consequences of that sudden
conversion much worse.

There could also be a driver bug that *always* does the heavyweight
cache flush.  Beats me.  Worth looking at.


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