dd question

[Adam Vande More]

On Sat, Sep 26, 2015 at 8:59 AM, William A. Mahaffey III <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