On Sat, Jun 17, 2006 at 12:19:21PM +0100, Rodrigo Ventura wrote:
>
> Hello again,
>
> I'm trying to make sure there is no shoe-shinning effect on my tapes.
> Examining amdump report I get:
>
> DUMP SUMMARY:
> DUMPER STATS
> TAPER STATS
> HOSTNAME DISK L ORIG-KB OUT-KB COMP% MMM:SS KB/s
> MMM:SS KB/s
> ------------------------------------- ------------------------------------
> -------------
> [...]
> omni /var/spool/imap/user/mn 2 119830 68203 56.9 0:39 1751.1
> 0:23 3018.5
> omni /var/spool/imap/user/op 0 6135350 4260802 69.4 35:28 2002.2
> 35:28 2002.0
> [...]
>
> The first line seems ok, since the nominal tape speed is about 3000KB/s,
> but the second one (2002KB/s) concerns me.
>
> However, it is the same rate as the dumper. What does it mean?
It means it was dumped directly to the tape, bypassing the holding disk.
Perhaps the dump was larger than the available space or your reserve
setting cut down the space available to level 0 dumps (the default
reserve is 100% for incrementals, level 0's not allowed.
>
> I was assuming that the hold disk is used to hold chunks of tar dump data,
> and these chunks are directly fed into the tape. Is this correct?
No, the holding disk collects dumps, possibly multiple simultaneously,
as they are running. When completed (note the complete dump collects
on the holding disk) then taper will transfer it as fast as possible
to the tape. Your dump is going only as fast as the archive program
can generate it, transfer it to the server over the network, and then
send it to the tape.
--
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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