Re: [Testbed-admins] Customizing Generic Image

[Mike Hibler <mike@flux.utah.edu>]

Actually, my interpretation of the second number was bogus.  It is supposed to
be the number of "chunks" remaining to decompress/load.  When reading from
stdin ('-'), it cannot figure how many total chunks there are, so it sets that
to zero and the result is ever increasing negative numbers.  So you output is
right and mine is wrong.  Anyway, the question is why is it taking 100x longer
for your chunks to get written.  Either the disk is really, really slow or
we aren't writing what we think we are.  For the former do:

  sudo ssh pc2 dd if=/dev/zero of=/dev/$DSK bs=256k count=100

and see what rate you get.  We get around 42MB/sec:

  958 boss> sudo ssh pc171 dd if=/dev/zero of=/dev/ad1 bs=256k count=100
  100+0 records in
  100+0 records out
  26214400 bytes transferred in 0.626413 secs (41848422 bytes/sec)

If you get something slow, look at /var/run/dmesg.boot on the node and see
if there are any interesting messages from the kernel.

For the latter, run imagedump on the image.  If you don't have imagedump on
your boss, go into the emulab build tree os/imagezip directory and do
"gmake imagedump" and run it from there.  This will print out some stats about
the image:

  955 boss> imagedump /usr/testbed/www/downloads/FBSD62+FC6-GENERIC.ndz
  /usr/testbed/www/downloads/FBSD62+FC6-GENERIC.ndz: 701497344 bytes, 669 chunks, version 2
    7306364 bytes of overhead/wasted space ( 1.04% of image file)
    5002 total regions: 7.5/1/157 ave/min/max per chunk
    694190980 bytes of compressed data
     3.58x compression of allocated data (2482524160 bytes)
    28.84x compression of total known disk size (20020396032 bytes)
    4343 free ranges: 4038192/32768/13588194304 ave/min/max size
    5002 allocated ranges: 496306/1024/18660864 ave/min/max size
    size distribution:
      <    4k bytes:    210  4.2%  4.2%
      <    8k bytes:    438  8.8% 13.0%
      <   16k bytes:    492  9.8% 22.8%
      <   32k bytes:    889 17.8% 40.6%
      <   64k bytes:    627 12.5% 53.1%
      <  128k bytes:    559 11.2% 64.3%
      <  256k bytes:    539 10.8% 75.0%
      >= 256k bytes:   1248 25.0%

On Wed, Nov 11, 2009 at 11:16:18AM -0800, Timothy Ficarra wrote:
> I've been running the imageunzip for close to 2 hours now. Here's what it presently looks like:
> 
> boss# sudo ssh pc2 imageunzip -o - /dev/$DSK < /usr/testbed/images/$FULL-GENERIC.ndz
> ...................................................................1534??? -67
> ...................................................................3043?? -134
> ...................................................................4698?? -201
> ...................
> 
> I'm curious about the negative values.
> 
> Regards,
> T Ficarra
>