Hope this is useful. I'm not currently subscribed to the mailing list, so
please Cc: any replies. (I took the wishlist from amanda 2.4.2p2, hope none
of the below is already in the wishlist for 2.4.3).
Simple:
- support ipv6
- encrypt with ssl (not just limit encryption to kerberos users)
- instead of 'crc' use 'sha1' or 'rmd160' in the current WISHLIST
- auto-loading of tapes in a tape silo
Complex:
- tape defragmentation + multiple backups on multiple tapes
- 'all versions of this file' in amrecover
Explanation:
With adsm (now part of tivoli) in IBM's backup solution, there is something
very similar to 'amrecover'. You can specify the dump date, and it will
load the tape(s) necessary to recover the data, and then recover it as
you ask it to.
There is definately the concept (already in the wishlist) in adsm of
the ability to specify a filesystem as a backup medium (actually, specifying
the number of 'large files of x size' is specified, then they are created,
each one as a 'volume', a tape is also a 'volume').
The defragmentation I hope I explain properly, if not, ask for more/better
explanation. To need defragmentation, you also need support for multiple
(partial)backups per tape. It is best done with alot of holding disk and
a tape silo, but can be done otherwise. The concept stems from adsm's
reality of doing a full backup once, then incremental always afterwards.
There is a concept of 'keep only one copy of a file if the most recent modification is
over x days old' and 'keep at max x copies of a file if the modification
times are since x days old' and 'keep all files since x days old'. This may
make more sense with an example:
- keep only one copy of each file if the most recent modification date
is older than 90 days
- keep at max 3 copies of a file if the modification times are newer
than 90 days
- or -
keep all files newer than 90 days
When you do things like the above, you end up having to go through a tape
that has many files backed up, and remove a few files that are outside
the scope of backup. The tape gets dumped to the holding area, and then
the data is manipulated to remove the files not needed in the backup system
anymore, then spooled with other data heading to tape. In general data
gets spooled to tape together, but each tape (or 'volume') gets fully
used each time it is written to.
The indexing mechanism for adsm required several tuning stages, since there
was a site I used to work for that used adsm that had a 500gb filesystem
with a poor algorithm for spreading out data (usually about 5 subdirs
deep to find a file and one or two files in the subdir, if any). It took
the indexing mechanism 22 hours to do a search for what to backup, then
about 20 minutes to do the actual backup.
It could get time consuming, perhaps the indexes would save time, but the
concept of doing 'ls -allverions file' and seeing each version of a specific
file that is in the backup set was extremely useful in adsm, users that
were very uncertain as to when the file was removed could be told we have
a file from the 10th, the 11th, and the 13th.
--
Todd Fries .. [EMAIL PROTECTED]
(last updated $ToddFries: signature.p,v 1.2 2002/03/19 15:10:18 todd Exp $)
