On Monday 02 June 2003 11:13, Brendon Colby wrote:
>Greetings,
>
>I just have a couple of questions that I couldn't get fully answered
> from the archives.
>
>1. If I have a 16 tape tapecycle, and a dumpcycle of 7, does this
> mean I effectively have 16 days of backups? As in, I can do a
> restore of up to 16 days? (I'm just trying to wrap my head around
> this new-to-me backup method.)
Not normally. Setting the dumpcycle to 7 is how you give amanda
notice as to how many days amanda has to do one full on everything in
the disklist. runspercycle is how you tell amanda how many actual
runs amanda will get in the realtime dumpcycle to do it all.
If you then had to recover, you would need only the last 'dumpcycle'
tapes. Note that I didn't say 7 though, because you might be running
a 5 day a week runspercycle, so that would be only the last 5 tapes.
However, having 16 tapes just means that in the event the most recent
is defective, then you have one more, even older backup to draw upon.
>2. If I disable hardware compression and use software compression,
> how would that affect my tapetype definition?
One would use the capacity the makers says it has when the compression
is turned off. Software is the prefered method, for 2 reasons.
1. gzip can normally outcompress the hardware compressors in most
drives. Night before last, the disklist and dumpcycle positioning
was such that I put something over 10 gigs on a 4 gig DDS2 tape. Of
course I don't do that every nite :)
2. amanda counts bytes sent to the tape. If the hardware compression
is on, then amanda has no clear view of the tapes capacity and will
happily write till it hits EOT if you are feeding it already
compressed files, like a whole dir full of rpm's or tar.bz2's, which
will probably grow some in the compressor. So you have to set the
tapetype to something less than the makers propaganda claims & then
(optionally, I've not been able to prove its effective) sacrifice a
chicken. If its turned off, then amanda has a pretty good view of
what the tape can hold and will fill it reliably to 95+% without ever
hitting the tapes EOT.
There is an amtapetype utility in the distribution that can test that
for you. But start it early in the day, it takes a while to run.
>define tapetype DLT8000 {
> comment "Quantaum (IBM) DLT-8000"
> length 37482 mbytes
> filemark 2362 kbytes
> speed 5482 kps
>}
>
>(I got that off the list.)
>
>3. Does anyone running Debian Woody use xfsdump? I'm having trouble
> getting that to work without having to recompile (not ideal) so I'm
> testing with tar right now. (I get the "disk not available?" error
> when I softlink /sbin/dump to /sbin/xfsdump.) Wouldn't native dump
> be the ideal method?
>
>
>Thanks.
--
Cheers, Gene
AMD K6-III@500mhz 320M
Athlon1600XP@1400mhz 512M
99.26% setiathome rank, not too shabby for a WV hillbilly
Yahoo.com attornies please note, additions to this message
by Gene Heskett are:
Copyright 2003 by Maurice Eugene Heskett, all rights reserved.
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