Re: [RFH] Partition table recovery

[Al Boldi <a1426z@gawab.com>]

Theodore Tso wrote:
> On Sat, Jul 21, 2007 at 07:54:14PM +0200, Rene Herman wrote:
> > sfdisk -d already works most of the time. Not as a verbatim tool (I
> > actually semi-frequently use a "sfdisk -d /dev/hda | sfdisk" invocation
> > as a way to _rewrite_ the CHS fields to other values after changing
> > machines around on a disk) but something you'd backup on the FS level
> > should, in my opinion, need to be less fragile than would be possible
> > with just 512 bytes available.
>
> *IF* you remember to store the sfdisk -d somewhere useful.  In my "How
> To Recover From Hard Drive Catastrophies" classes, I tell them to
> print out a copy of "sfdisk -l /dev/hda ; sfdisk -d /dev/hda" and tape
> it to the side of the computer.  I also tell them do regular backups.
> What to make a guess how many them actually follow this good advice?
> Far fewer than I would like, I suspect...
>
> What I'm suggesting is the equivalent of sfdisk -d, except we'd be
> doing it automatically without requiring the user to take any kind of
> explicit action.  Is it perfect?  No, although the edge conditions are
> quite rare these days and generally involve users using legacy systems
> and/or doing Weird Shit such that They Really Should Know To Do Their
> Own Explicit Backups.  But for the novice users, it should work Just
> Fine.

Sounds great, but it may be advisable to hook this into the partition 
modification routines instead of mkfs/fsck.  Which would mean that the 
partition manager could ask the kernel to instruct its fs subsystem to 
update the backup partition table for each known fs-type that supports such 
a feature.


Thanks!

--
Al