clear metadata using dd?
olli at lurza.secnetix.de
Tue Jan 23 18:48:58 UTC 2007
Eric Anderson wrote:
> Oliver Fromme wrote:
> > Fernan Aguero wrote:
> > > adxs1, swap
> > > adxs2, gmirror
> > > adxs3, gstripe
> > Can someone please explain why such a setup makes sense?
> > As far as I can tell, the purpose of gmirror is to provide
> > redundancy in the case of drive failure. I.e. if one
> > drive fails, the system keeps running happily instead of
> > crashing.
> > But if only part of the disk is mirrored, then the system
> > will still crash if one drive fails. So what is the point
> > of using gmirror, if not on whole disks?
> You might crash, but the data on the mirror on one of the disks is still
> there, so you haven't lost all the data.
Right, but you have lost all the data in the partitions that
are not mirrored. The system is basically unusable and will
need to be restored from backup.
In this particular case, if I understood Fernan correctly,
the mirror contains the root file system, while all other
data is on a gstripe (not mirrored). So if a drive fails,
the system crashes and all of the actual user data is
lost. The fact that you still have a good root file
system on one of the disks doesn't help much in that
Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing
Dienstleistungen mit Schwerpunkt FreeBSD: http://www.secnetix.de/bsd
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