On Tue, Nov 08, 2005 at 02:54:20PM +0100, Montagni, Giovanni wrote:
>>
>> -----Messaggio originale-----
>> Da: owner-amanda-users AT amanda DOT org [mailto:owner-amanda-users AT
>> amanda DOT org] Per conto di Gene Heskett
>> Inviato: martedì 8 novembre 2005 14.23
>> A: amanda-users AT amanda DOT org
>> Oggetto: Re: 2 tapes backup...
>>
>>
>> On Tuesday 08 November 2005 03:11, Montagni, Giovanni wrote:
>> >My backup have to use 2 different tapes to do full dumps.
>> >I read the amanda's docs, but i can't understand how can i tell to
>> >amanda to use 2 tapes without tape changer (i use an lto drive so i
>> >have to change tape manually at the morning when i arrive to work, tha
>> >backup start late at night). I tried with chg-manual, but i can't
>> >switch tape when it is ran by cron.
>>
>> Why not? The change tape message should be waiting for you in the morning,
>> and when you've changed the tape, amanda should be able to resume, having
>> completed the backup to the holding disk in the meantime. So all it
>> needs to do is flush the remainder. Or, maybe you have to issue the
>> amflush command when you've changed the tape in the morning. I'm not
>> 100% sure, never having used chg-manual personally.
>>
>> You need enough holding disk for that of course.
>> Not having enough holding disk seriously limits amanda's abilities.
>>
> I don't use the holding disk, because i don't have enough free space
>> to store data twice (the data itself and backup).
>
The holding disk only stores untaped data. Not all the data will be
on the holding disk at the same time. And if you are using software
compression the dumped data will be smaller than the original. While
it would be nice to have sufficient free space as your total data,
the holding disk need not be that large.
>From a cost perspective, your lto drive cost multi-thousand dollars
if I read the market correctly. And tapes cost $30 or more each.
It would be only a few percentage points of your total backup investment
to add an inexpensive disk and dedicate it to holding disk space.
The benefits would be improved total time of backup due to parallelism
of multiple, simultaneous dumps and completion of the dump before you
arrive the next morning. As it stands now, only one DLE (Disk List
Entry) can dump at a time. And, even with a second tape, the dump
will continue the next morning while people are working.
However, you don't need a holding disk to use chg-manual. But
there is little to go on from your description of your attempts.
What changes did you make to amanda.conf to "try with"
chg-manual? Was runtapes one of them? What was your observation
that it did not work? Did you read the comments in chg-manual?
Hint, always a good idea with script as they may point out some
parameters the need to be set. As I recall, by default
chg-manual will notify you on your terminal to change the tape.
If this is run from cron there will be no terminal. But there
is, in the script, a way of changing from terminal messages to
email messages.
With a holding disk, the next morning when you change the tape,
amanda would just dump the untaped archives to the second tape.
But without the HD, amanda will resume its dumping, compressing,
indexing, network traffic, and taping. All during business hours.
In addition to the impact that may make on your users, it also
means amanda is backing up file systems while they are actively
in use and possibly changing. Never a good idea.
No, you don't need a holding disk, but get one!
jl
--
Jon H. LaBadie jon AT jgcomp DOT com
JG Computing
4455 Province Line Road (609) 252-0159
Princeton, NJ 08540-4322 (609) 683-7220 (fax)
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