Backup Central

Good question. I would like to know as well. As for me, I pretty much
always pre-position to the file number with mt. I hadn't realized
amanda didn't do that.

Chris Miller wrote:

"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




--

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jason Brooks ~ (503) 641-3440 x1861
Direct ~ (503) 924-1861
Email to: jason.brooks < at > windriver.com
Twiki: http://twiki.wrs.com/do/view/Main/JasonBrooks

Senior Systems Administration Analyst
Wind River Systems
8905 SW Nimbus ~ Suite 255
Beaverton, Or 97008

Hello,

I found this in the amanda.conf.in file. It's new to me. I have been
using my same amanda.conf file since 2.4.2p1, so go figure.

amrecover_do_fsf yes # amrecover will call amrestore with the
# -f flag for faster positioning of the tape.
amrecover_check_label yes # amrecover will call amrestore with the
# -l flag to check the label.
amrecover_changer " < at > DEFAULT_TAPE_DEVICE < at > " # amrecover will use the
changer if you restore
# from this device.
# It could be a string like 'changer' and
# amrecover will use your changer if you
# set your tape with 'settape changer'



Jason Brooks wrote:

Good question. I would like to know as well. As for me, I pretty
much always pre-position to the file number with mt. I hadn't
realized amanda didn't do that.

Chris Miller wrote:

"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






--

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jason Brooks ~ (503) 641-3440 x1861
Direct ~ (503) 924-1861
Email to: jason.brooks < at > windriver.com
Twiki: http://twiki.wrs.com/do/view/Main/JasonBrooks

Senior Systems Administration Analyst
Wind River Systems
8905 SW Nimbus ~ Suite 255
Beaverton, Or 97008