Date: Sat, 26 Sep 2015 09:17:18 -0453.75 From: "William A. Mahaffey III" <wam@hiwaay.net> To: FreeBSD Questions !!!! <freebsd-questions@freebsd.org> Subject: Re: dd question Message-ID: <5606A7A4.5000301@hiwaay.net> In-Reply-To: <5606A4FF.4090105@hiwaay.net> References: <5606A4FF.4090105@hiwaay.net>
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On 09/26/15 09:05, William A. Mahaffey III wrote:
>
>
> I am preparing a USB stick for use to install FreeBSD 9.3R on 2 new
> boxen I am bringing online. I already had the FreeBSD 9.3R img dd'ed
> to that stick last year when I provisioned this box, but for some
> reason, when I plugged the stick into my USB port today to copy some
> additional files to it (scripts to be used during installs to
> partition & slice up HDD's), I got errors in my syslog file & couldn't
> mount the drive for the copies. No problema, I'll just re-dd the image
> to the device & start over, all I would lose is output from the
> previous install (this box, last year this time). However, I notice
> the dd is proceeding *VERY* slowly:
>
>
> [root@kabini1, /etc, 8:47:59am] 508 % ll /dev/da0*
> crw-r----- 1 root operator 0xd2 Sep 26 08:29 /dev/da0
> crw-r----- 1 root operator 0xcd Sep 26 08:29 /dev/da0a
> [root@kabini1, /etc, 8:48:09am] 509 % ll
> /net/q6600/home/ISOs/BSDs/FreeBSD/9.3/
> total 1530556
> -rw-r--r-- 1 wam users 178749440 Jul 26 2014
> FreeBSD-9.3-RELEASE-amd64-bootonly.iso
> -rw-r--r-- 1 wam users 671152128 Jul 26 2014
> FreeBSD-9.3-RELEASE-amd64-disc1.iso
> -rw-r--r-- 1 wam users 717373440 Jul 26 2014
> FreeBSD-9.3-RELEASE-amd64-memstick.img
> -rw------- 1 wam users 811 Jul 26 2014 checksum.MD5.txt
> [root@kabini1, /etc, 8:48:19am] 510 % dd
> if=/net/q6600/home/ISOs/BSDs/FreeBSD/9.3/FreeBSD-9.3-RELEASE-amd64-memstick.img
> of=/dev/da0
> 94834+0 records in
> 94834+0 records out
> 48555008 bytes transferred in 542.035379 secs (89579 bytes/sec)
> 101599+0 records in
> 101599+0 records out
> 52018688 bytes transferred in 580.466607 secs (89615 bytes/sec)
>
> I got that output by sending the SIGINFO signal to the dd process from
> another shell window. My question is: Why so slow (89-ish KB/s) ? I
> have gigabit switched LAN (125 MB/s theoretical speed), & most other
> file copies or rsyncs across the LAN go at about 1/3 - 1/2 of
> theoretical speeds, which is AOK by me. Any ideas ? TIA & have a nice
> weekend.
Update: I got tired of waiting & just copied the img files over from the
other box to do the dd in case the interaction of dd & NFS were a problem:
[root@kabini1, /etc, 9:12:23am] 511 % cp
/net/q6600/home/ISOs/BSDs/FreeBSD/9.3/FreeBSD-9.3-RELEASE-amd64-memstick.img
.
[root@kabini1, /etc, 9:12:39am] 512 % dd
if=FreeBSD-9.3-RELEASE-amd64-memstick.img of=/dev/da0
3049+0 records in
3049+0 records out
1561088 bytes transferred in 17.511796 secs (89145 bytes/sec)
^C9584+0 records in
9583+0 records out
4906496 bytes transferred in 54.403733 secs (90187 bytes/sec)
[root@kabini1, /etc, 9:13:51am] 513 %
[root@kabini1, /etc, 9:13:51am] 513 %
[root@kabini1, /etc, 9:13:52am] 513 %
[root@kabini1, /etc, 9:13:52am] 513 % uname -a
FreeBSD kabini1.local 9.3-RELEASE-p24 FreeBSD 9.3-RELEASE-p24 #0: Sat
Aug 22 01:54:44 UTC 2015
root@amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC amd64
[root@kabini1, /etc, 9:13:55am] 514 %
Note that the cp happened pretty quick, 717-ish MiB in about 15 sec., or
around 45-ish MB/s, about 1/3 of max, quite acceptable to me. Obviously,
the dd is still excruciatingly slow .... What gives ? TIA & have a nice
weekend ....
--
William A. Mahaffey III
----------------------------------------------------------------------
"The M1 Garand is without doubt the finest implement of war
ever devised by man."
-- Gen. George S. Patton Jr.
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