Amanda overwrites level 0 dumps?
2003-10-26 11:46:35
Hi,
it has now happened several times over the past few months that the
Amanda planner failed to schedule level 0 dumps in a timely manner. I'm
using the Amanda 2.4.4 package that ships with SuSE 8.2. There is no
pertinent information in the Changes section of 2.4.4p1 (I looked at the
sourceforge release notes).
Relevant configuration:
- no changer
dumpcycle 14 days # the number of days in the normal dump cycle
tapecycle 6 tapes # the number of tapes in rotation
bumpsize 1500 Mb # minimum savings (threshold) to bump level 1 -> 2
bumpdays 1 # minimum days at each level
bumpmult 4 # threshold = bumpsize * (level-1)**bumpmult
runtapes 1 # number of tapes to be used in a single run of amdump
The results have been that I lost the last level 0 dump because it was
overwritten with level 1 dumps.
I've seen this happen in various circumstances:
* Manual backups have been run outside the schedule (I rotate 6 tapes in
14 days).
* Machines are unavailable for an extended amount of time.
What I expect of Amanda:
* NEVER overwrite a level 0 dump, not even with another level 0.
If the write fails, there is no backup left over to restore from.
* I'd prefer if Amanda refused to write to a tape if that would mean
killing a level 0 dump.
In this discussion, level 0 also applies to level 1 -> level 2 dumps,
Amanda shouldn't overwrite one level 1 dump unless there is a newer one.
If there is not enough space to keep an older level 0 dump as a new one
is written, then abort, moaning and screaming loudly "buy more tapes" as
the backup will be worthless.
This means: if I have 6 tapes, Amanda will have to write level 0 every
FIFTH dump (not every SIXTH) at the latest. Of course, the "planner"
(scheduler) can promote to level 0 earlier if that's necessary for
capacity reasons.
One thing I've never understood is: WHY does Amanda need to know the
dumpcycle in days? If this feature has precedence over the tapecycle, it
is broken.
--
Matthias Andree
Encrypt your mail: my GnuPG key ID is 0x052E7D95
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