dd question

[William A. Mahaffey III]

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 at 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 at 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 at 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 at kabini1, /etc, 9:12:23am] 511 % cp 
/net/q6600/home/ISOs/BSDs/FreeBSD/9.3/FreeBSD-9.3-RELEASE-amd64-memstick.img 
.
[root at 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 at kabini1, /etc, 9:13:51am] 513 %
[root at kabini1, /etc, 9:13:51am] 513 %
[root at kabini1, /etc, 9:13:52am] 513 %
[root at 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 at amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC amd64
[root at 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."
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