Re: config question (external raid, external log?)

[Thor Lancelot Simon <tls@xxxxxxxxxxxx>]

On Mon, May 27, 2002 at 09:30:29PM +0200, Ragnar Kjørstad wrote:
> On Mon, May 27, 2002 at 07:14:26PM +0000, Robert Sander wrote:
> > On Mon, 27 May 2002 16:36:24 +0000 (UTC),
> >  utz lehmann <xfs@xxxxxxxxxx> wrote:
> > > A warning. All SCSI to IDE RAID Systems i know have non battery backuped
> > > cache. In the case of a power outage all unwritten data (and filesystem
> > > metadata) in the RAID cache is lost. This cause filesystem corruption.
> > > Running a journaled fs with a volatile cache is not recomended.
> > 
> > Thanks for the warning but the system will have a UPS with enough
> > capacity to savely shutdown if the power does not return within 5
> > minutes.
> 
> The problem remains for crashes or hangs.

No, it does not -- not unless you're talking about "crashes or hangs of
the firmware in the external RAID controller", in which case it would be
entirely possible for it to mixmaster your data whether it had local
battery backup for its cache or not.

Thor