Amanda-Users

amrecover and tape seeking

2004-05-20 04:19:19
Subject: amrecover and tape seeking
From: Chris Miller <ctodd AT netgate DOT net>
To: amanda-users AT amanda DOT org
Date: Wed, 19 May 2004 23:44:35 -0700 (PDT)
"amadmin find" shows a record of the location on tape (record number)
where each dump record exists. Given this information, why does amrecover
start at the beginning of the tape during a restore and read each record
sequentially on the tape until it finds the correct record? I can
significantly reduce restore times by suspending amrecover and using "mt
fsf <n>" to pre-position the tape one or two records before the record it
wants. I gather the code is doing a pattern match for hostname, diskname,
and date. Why not use this information to get the record number and
position the tape appropriately?

Currently I average 150 records per DLT 40/80 and it takes forever to do a
restore, particularly when multiple records are needed from the same tape
and amrecover rewinds the tape after each restore unnecessarily given
the newer dumps are at the end of the tape. (yes, I am using the
no-rewind device :-).

I realize it's safer to start from the beginning of the tape, but after a
few "all nighters" down at the data center over the years, this is a
question that's plagued me given the several versions released. Just want
to understand the logic or respectfully request an enhancement.

Kind regards,
        Chris

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