On Tue, 13 Jun 2006 at 12:55pm, Toralf Lund wrote
Paul Bijnens wrote:
Taping one DLE is several "runs" opens a can of worms: you have to
add a notion of "partial" succeeded. Restoring then needs some tapes
and some holdingdisk files. What if the holdingdisk crashes or
accidently rm the files before all of it is written to tape? etc.
This would be a bit of an issue, of course. I'm wondering if the would the
situation be that much different from the one we have today, though. Holding
disk crash or file removal is always going to be a serious problem, of
course. But if you have a partial tape dump of the data, you will at least be
able to recover some of it... Maybe it would be wise to keep all data on the
To throw my $.02 in here, the situations would be very different. If one
is "forced" to have all DLEs "tapeable" in one amdump run, then
(theoretically), nothing will be left on the holding disk to lose should
said disk die. That's obviously not the case if single DLEs are allowed
to span amdumps, and the holding disk dies between amdumps.
Having the entire night's amdump run on tape at the end of the amdump
gives me that warm fuzzy feeling inside. Maybe it's just me being
curmudgeonly (it wouldn't be the first time -- hell, I haven't found a WM
I like more than fvwm2) and slavishly adhering to the KISS method. But I
think backups *should* adhere to the KISS method.
What happens in the current version if amdump is interrupted while writing
the 2nd tape, by the way?
I assume the same thing that would happen if amdump were interrupted while
writing to the 1st tape. The image being written to tape would be marked
FAILED TO TAPE and be left on the holding disk (along with any other
images that hadn't been written yet), and the user would be encouraged to
run amflush.
--
Joshua Baker-LePain
Department of Biomedical Engineering
Duke University