Jim Buzbee schrieb:
>
> Simon Matter wrote:
>
> ...
>
> > Jim,
> >
> > It's obvious that lifetime is reduced with write caching off. Just
> > listen to the drive and compare between w/cache on / off. What helps
> > here is that Linux uses memory for caching effectively.
> >
> > Some weeks ago I brought an issue to this list. I got zero filled files
> > after _clean_ reboots and I thought it was the write cache of the IDE
> > drives not flushing correctly. In fact I got bitten by the 'remount
> > readonly bug' and it had nothing to do with the write chache being
> > turned on.
>
> I think I missed some of the "remount readonly" discussion. Can someone
> summarize what the problem is and the correct way we should be doing a
> controlled shutdown/reboot with XFS?
The problem was that I changed some xinetd services via ntsysv (RH
specific) and immediately rebooted. Something like this:
ntsysv ; shutdown -r now
Shutdown was okay and / got remounted ro. After reboot, all the files in
/etc/xinetd.d that were touched by ntsysv before shutdown were now
filled with zero. In the end it came out that it was a bug of this
kernel which is fixed now.
You may want to check this:
http://oss.sgi.com/projects/xfs/mail_archive/200203/msg00634.html
-Simon
>
> ...
>
> >
> > Cache flushing does only work if the drive honours the flushing request
> > correctly. What I recommend is trying to use drives which:
> > - really flush cache when requested to do so.
> > - flush cache on power failure.
>
> The drive we are currently using does its best. It has a "power
> failure" mode where the cache is flushed. I believe they re-order
> requests to get as much data on the platter as possible in this mode.
> We're trying to determine how how much time they have after the power is
> cut.
>
> Jim Buzbee,
> Echostar Technologies
>
> >
> > The latter is quite important because comsumers will just pull power to
> > turn it off. I don't know whether this feature is available with IDE
> > drives but I think it should be possible.
> >
> > -Simon
> >
> > >
> > > This has to be a common problem. Does anyone have any strategies or
> > > words of wisdom?
> > >
> > > Jim Buzbee,
> > > Echostar Technologies
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