dd question

[William A. Mahaffey III]

On 09/26/15 10:25, Adam Vande More wrote:
>
>
> On Sat, Sep 26, 2015 at 8:59 AM, William A. Mahaffey III 
> <wam at hiwaay.net <mailto:wam at hiwaay.net>> 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.
>
>
> Hitting Ctrl-T in the dd terminal is a lot easier.
>
>     My question is: Why so slow (89-ish KB/s) ?
>
>
> Well first off I'd tell dd to use a bigger bs like 1m.
>
>
> -- 
> Adam


Very well, I may try that experimentally. Meanwhile I got tired of 
waiting (again) & moved the USB drive to my last remaining Linux box & 
did the dd there:


[root at Q6600:/etc, Sat Sep 26, 10:01 AM] 1018 # dd 
if=/home/ISOs/BSDs/FreeBSD/9.3/FreeBSD-9.3-RELEASE-amd64-memstick.img 
of=/dev/sdg
342905+0 records in
342905+0 records out
175567360 bytes (176 MB) copied, 46.5117 s, 3.8 MB/s
440625+0 records in
440625+0 records out
225600000 bytes (226 MB) copied, 78.495 s, 2.9 MB/s
584961+0 records in
584961+0 records out
299500032 bytes (300 MB) copied, 112.507 s, 2.7 MB/s
938865+0 records in
938865+0 records out
480698880 bytes (481 MB) copied, 199.845 s, 2.4 MB/s
1401120+0 records in
1401120+0 records out
717373440 bytes (717 MB) copied, 348.004 s, 2.1 MB/s
[root at Q6600:/etc, Sat Sep 26, 10:07 AM] 1019 # uname -a
Linux Q6600 2.6.35.14-106.fc14.x86_64 #1 SMP Wed Nov 23 13:07:52 UTC 
2011 x86_64 x86_64 x86_64 GNU/Linux
[root at Q6600:/etc, Sat Sep 26, 10:54 AM] 1020 #


I will retry the dd later or on another spare drive to assess. This is a 
bit distressing if that doesn't go well, however, as I am going to 
reprovision the Linux box to either CentOS 6 (generation-wise similar to 
the FC 14 already there) or FreeBSD 9.3R, cutting ties w/ Linux 
altogether. However, I do occasionally need dd to work correctly, & if I 
am going to lose that moving away from Linux, that would be a 
significant factor in my decision making.


-- 

	William A. Mahaffey III

  ----------------------------------------------------------------------

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