[Novalug] need dd help
Jay Hart
jhart@kevla.org
Tue Feb 14 07:26:45 EST 2012
For the second disk, I up'ed bs from 1k to 1M. Look at the difference:
[jay@freenas] /dev/ufs# dd if=/dev/zero of=/dev/ada0 bs=1k
dd: /dev/ada0: end of device
976762585+0 records in
976762584+0 records out
1000204886016 bytes transferred in 85322.193527 secs (11722681 bytes/sec)
[jay@freenas] /dev/ufs# dd if=/dev/zero of=/dev/ada1 bs=1M
dd: /dev/ada1: short write on character device
dd: /dev/ada1: end of device
953870+0 records in
953869+1 records out
1000204886016 bytes transferred in 10792.327848 secs (92677400 bytes/sec)
Hugh difference in completion time.
Jay
> On Mon, Feb 13, 2012 at 07:46:55PM -0500, Jay Hart wrote:
>> Ok,
>>
>> [jay@freenas /]$ iostat
>> tty da0 ada0 ada1 cpu
>> tin tout KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s us ni sy in id
>> 0 1 5.39 0 0.00 1.00 11094 10.83 2.17 0 0.00 2 0 45 23
>> 30
>>
>> What does this mean???
>>
> Jay, I won't interpret it, but only point out that you need to
> add an interval time, and possibly a count argument, to get
> multiple reports. For both vmstat and iostat the first report
> is data since the last reboot.
>
> $ iostat 2 3
> Linux 3.2.5-3.fc16.x86_64 (vost.jgcomp.com) 02/13/2012 _x86_64_ (2 CPU)
>
> avg-cpu: %user %nice %system %iowait %steal %idle
> 0.56 0.10 0.83 0.01 0.00 98.50
>
> Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn
> sda 0.90 16.36 8.73 1242018 662852
>
> avg-cpu: %user %nice %system %iowait %steal %idle
> 2.00 0.00 2.00 0.00 0.00 96.00
>
> Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn
> sda 3.50 0.00 42.00 0 84
>
> avg-cpu: %user %nice %system %iowait %steal %idle
> 1.76 0.00 1.51 0.00 0.00 96.73
>
> Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn
> sda 1.00 8.00 0.00 16 0
>
>
> --
> Jon H. LaBadie novalugml@jgcomp.com
> 11226 South Shore Rd (703) 787-0688 (H)
> Reston, VA 20190 (609) 477-8330 (C)
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