Re: io performance...

[Jeff V. Merkey]

Max Waterman wrote:

> Jeff V. Merkey wrote:
>
> > Max Waterman wrote:
> >
> > > One further question. I get these messages 'in' dmesg :
> > >
> > > sda: asking for cache data failed
> > > sda: assuming drive cache: write through
> > >
> > > How can I force it to be 'write back'?
> >
> >
> >
> >
> > Forcing write back is a very bad idea unless you have a battery 
> > backed up RAID controller.  
>
>
> We do.
>
> In any case, I wonder what the consequences of assuming 'write 
> through' when the array is configured as 'write back'? Is it just 
> different settings for different caches?


It is.  This is something that should be configured in a RAID 
controller.  OS should always be write through.

Jeff

> Max.
>
> > Jeff
> >
> > > Max.
> > > -
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