Chris,
HW compression is great for preserving the server's cpu but
doesn't allow amanda to get an historical estimate of the
compressability of the partition.
I truely don't know what the official answer is...but what I
have done for a couple of my systems (I prefer SW compression
on the client to HW because of the estimate issue, but will
on occasion utilize HW comp) is to extend the tape length by
the compression factor... if you have SW 40% compression and a
100Gig tape you might specify HW compression and a 140 Gig tape.
At least that is what I have done, YMMV.
Brian
On Wed, Jan 03, 2007 at 12:01:50PM -0700, Chris Cameron wrote:
> This seems like it'd be a common occurrence but I've looked all over.
>
>
> I have a DLT-8000. 40/80 Gig tapes. I want to backup a 50 gig partition
> and am going to use hardware compression. Amanda says the dump won't fit.
>
> This configuration was working with server compression turned on and a
> different tape drive.
>
> Error:
>
> NOTES:
> planner: cgydc002 /dev/vg01/lv_data 20070103 0 [dump larger than tape,
> 53128750 KB, full dump delayed]
> taper: tape Wk2Tue kb 2088288 fm 4 [OK]
>
>
> My tape type:
> define tapetype DLT8000-40 {
> comment "just produced by tapetype program"
> length 37482 mbytes
> filemark 2362 kbytes
> speed 5482 kps
>
> }
>
> My dump type:
> define dumptype full-hlding-high-cgy {
> comment "Full backup"
> # compress server fast
> compress none
> program "GNUTAR"
> dumpcycle 0
> priority high
> strategy noinc
> holdingdisk no
> index yes
> exclude "./dcbackup"
> }
>
>
> What do I need to do to have AMANDA try writing this all to tape? I
> realize it can't know how well the hardware compression will do, but
> trying to fit 50 gigs compressed on a 40 gig tape doesn't seem unreasonable.
>
> I'm running Amanda-2.4.4p4. I've tried "comprate 0.50" with no success.
>
> Thanks,
> Chris
---
Brian R Cuttler brian.cuttler AT wadsworth DOT org
Computer Systems Support (v) 518 486-1697
Wadsworth Center (f) 518 473-6384
NYS Department of Health Help Desk 518 473-0773
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