On Tuesday 19 October 2004 17:00, Daniel Bentley wrote:
>The boss has just decreed that we need to increase retention for
> desktop backups, and has noted that we've been very good
> financially and need to spend more of our budget to keep it out of
> the hands of Uncle Sam. ;)
>
>So, anyone have suggestions on external changer devices, 8 tape
> capacity? Any brands/model families you would particularly
> recommend, or would recommend we -avoid-? Also, as we've been
> dealing exlcusively with DDS here, what are pros- and cons- of the
> different media formats (AIT, DLT, LTO, etc) (linkage is
> appreciated too, I'm sure I'm not the first to ask this)? Any
> thoughts/recommendations on larger capacity single-drive devices,
> rather than a multi-tape configuration? Our current changer is
> only an old DDS-3 Sony STL-9000 (1 tape a day), so using a large
> tape over the course of a week certainly isn't beyond the realm of
> possibility as well...
>
>Sorry to send this out to the Amanda list, I just figure it's one of
> the better collectives of tape-device users to ask...
It generally is, however let me remind the questioner here that the
amanda design precludes useing a tape for more than one session. Too
much can happen to a device in between backup sessions that would
destroy any chance of the tape being in a position so that the next
backup was appended to an existing one. Because of that period when
the tape is not under amandas direct control, its just not worth the
chance to try to append when that append may inadvertantly wipe the
rest of the tape if the operator had ejected it to read the label in
the meantime.
So amanda is quite happy with most of the changer robots. I, if in
your shoes, would go for a larger library, one that could possibly
hold the whole tapecycles worth of tapes, and equip it with a drive
big enough to put each nights backup on a single tape. If the
library can hold all the tapes at once, and has a lockable front
access door, then that tends to remove the human curiosity,
janitorial tinkering and "Oh, I forgot" errors from your backup
protocol. I suspect that far more tapes have been damaged by human
handling than by the robot unless the robot is out of adjustment,
said mis-adjustment often being caused by human intervention in the
first place.
Most of us seem to migrate to a weeklong dumpcycle, and if changer
robot equipt, use a runspercycle of that same 7 days which allows
amanda to spread the load, equalizing the amount of data stored each
night as best she can. To that end, a disklist that is many smaller
pieces is preferable to one with only 6 entries of 25GB each as
amanda must then try to juggle the schedueling in 25GB pieces, not
terrible effective on a 50GB drive. Having several disklist entries
that are only 1 to 5% of the tape give amanda much more freedom to
plan and use the medium to its best advantage.
Thats my $0.02 worth. I'm a fan of the lady obviously.
--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
99.27% setiathome rank, not too shabby for a WV hillbilly
Yahoo.com attorneys please note, additions to this message
by Gene Heskett are:
Copyright 2004 by Maurice Eugene Heskett, all rights reserved.
|
