Fred,
I've hit a limit on at least on one of my amanda servers (yes, multiple,
14ish, I lose track).
I've found that the spool space is not being filled on my server
because the clients can't send the data any faster than they are.
Why that is in my case is probably different than yours and I've
found that "amplot" is an excellent tool to help determine where
the bottleneck might be. [Its only fair that I tell you about it
since I was fortunately enough to be told by others on the list]
You might even find its worthwhile to compress some partitions on
clients and some on the server, depending on where your free CPU
time is and where/if you have any network bottlenecks. Each DLE
can be individually selected for client/server/no compression,
though HW compression is an all or nothing deal.
Warning - never double compress a DLE !
As far as moving amanda to a high end system, all amanda does,
(which I say as a bit of a joke) is to manage the levels and
issue remote commands, handle the spool area and drive the tape.
All of the "dump/tar/compression" is typically handled by the client
systems. The driver end of amanda on the server is not CPU intensive
unless you perform server-side SW-compression.
On Mon, Aug 23, 2004 at 03:12:52PM -0400, Frederic Medery wrote:
> Thanks,
> in fact what I want is to speed up my backup so i moved my tape charger
> to the biggest server, now I have a /amanda with 160 GB of free space. I
> thought that HW compression would also speed up my backup.
>
> thanks again
>
> Frederic Medery
> System Administrator
>
> LexUM, University of Montreal
>
>
>
> Brian Cuttler wrote:
>
> >Fred,
> >
> >Fact
> >The options are not exclusive. You can SW compress on the client
> >or on the server or in the HW having nothing to do with the choice
> >of dump v tar.
> >
> >Opinion
> >HW compression is great if you are trying to save CPU on the client
> >or server, but doesn't allow you to estimate tape usage as well since
> >amanda doesn't learn from the drive what the compression ratios are
> >for the file systems you are dumping.
> >
> >er, I should say the DLE - disk list entries, since tar allows you
> >to put to tape (or disk file) things other than "partitions".
> >
> > YMMV
> >
> >On Mon, Aug 23, 2004 at 02:52:29PM -0400, Frederic Medery wrote:
> >
> >
> >>Hello, I'm using amanda with IBM 3581 tapechanger,
> >>my tapetypes.conf is :
> >>
> >># IBM LTO Ultrium 3581 tape Charger
> >>define tapetype IBM-LTO3581 {
> >> comment "IBM LTO Ultrium 3581 (Hardware Compression off)"
> >> length 100608 mbytes
> >> filemark 0 kbytes
> >> speed 13120 kps
> >>}
> >>
> >>
> >>I'm gonna use dump instead of tar so I want to enable hardware
> >>compression, but I can'y find any in the amanda doc ?
> >>
> >>Some Hints ??
> >>
> >>Thanks !!!!
> >>
> >>--
> >>Frederic Medery
> >>System Administrator
> >>
> >>LexUM, University of Montreal
> >>
> >>
> >>
> >---
> > 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
> >
> >
> >
---
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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