On Mon, Feb 04, 2008 at 07:38:40PM +0300, Michael Tokarev wrote:

Eric Sandeen wrote:
[]

quoted

http://oss.sgi.com/projects/xfs/faq.html#nulls

and note that recent fixes have been made in this area (also noted in
the faq)

Also - the above all assumes that when a drive says it's written/flushed
data, that it truly has.  Modern write-caching drives can wreak havoc
with any journaling filesystem, so that's one good reason for a UPS.  If

Unfortunately an UPS does not *really* help here.  Because unless
it has control program which properly shuts system down on the loss
of input power, and the battery really has the capacity to power the
system while it's shutting down (anyone tested this?  With new UPS?
and after an year of use, when the battery is not new?), -- unless
the UPS actually has the capacity to shutdown system, it will cut
the power at an unexpected time, while the disk(s) still has dirty
caches...

if the ups is supported by nut (http://www.networkupstools.org) you can
do this easily.
Obviously you should tune the timeout to give your systems enough time
to shutdown in case of power outage, and periodically check your
battery duration (that means real tests) and re-tune the nut software
(and when you discover your battery is dead, change it)

L.

-- 
Luca Berra -- bluca@comedia.it
        Communication Media & Services S.r.l.
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