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Date:      Fri, 31 May 2002 10:48:08 -0500
From:      "Jack L. Stone" <jackstone@sage-one.net>
To:        freebsd-questions@freebsd.org
Subject:   DD for HD backups
Message-ID:  <3.0.5.32.20020531104808.01c49f08@mail.sage-one.net>

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Running 4.5-RELEASE

This is more of an answer than a question... for the archives and the next
who may wonder about using dd to safely duplicate a hard disk & within a
reasonable amount of time.

A few days ago, I had asked about using dd to backup from one HD to
another. I wondered how long it would take for 10GB... at least a ballpark
guess would be good enough. The answer I got was that it depends on the
hardware, such as CPU, RAM, etc. Well, last night, I dove in first using my
test box with two identical 10GB HD. The objective was to move up to the
production boxes, each with two identical 40GBs. Here's the stats:

TEST BOX:
200MHz 96MB RAM 2 10GB HDs (old HDs)
started 8:29pm done 9.04pm = 35mins
cpu 7-10%
1252755+0 records in
1252755+0 records out
10262568960 bytes transferred in 2122.415942 secs (4835324 bytes/sec)

NOW, the BIG question: "would the HD-2 boot up and function exactly like
the HD-1..??"
ANSWER: YES! I merely switched the cables, rebooted and VOILA!

PRODUCTION BOX #1:
1.2GHz RAM 1GB 2 40GB IDEs ATA100s
started: 9:34pm done: 10:23pm = 49 mins
root@asafeserver>> dd if=/dev/ad0 of=/dev/ad1 bs=8192
4885335+0 records in
4885335+0 records out
40020664320 bytes transferred in 2952.664701 secs (13554084 bytes/sec)

PRODUCTION BOX #2:
1.4GHz 1GB RAM 2 40GB IDEs ATA100s
Started 9:46am 10:25am =39 mins
root@sage-one>> dd if=/dev/ad0 of=/dev/ad1 bs=8192
4886112+0 records in
4886112+0 records out
40027029504 bytes transferred in 2359.703037 secs (16962740 bytes/sec)

I am pleased.....

.... our website: http://www.sage-one.net/

Best regards,

Jack L. Stone
Server Admin

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