[CentOS] Shrinking a volume group

Steve Bergman steve at rueb.com
Wed Sep 13 15:58:34 UTC 2006

On Wed, 2006-09-13 at 08:42 -0700, Kirk Bocek wrote:
> Steve, show your math on how you calculated 58MB/sec from two timed processes. On an
> array on one of my servers, I show that the time approximately doubles when running
> two processes instead of each by themselves. That still yields about the same throughput.


131072*4k = 524,288k per dd process.

There are two of these processes running simultaneously, for a total
1,048,576k of data.

1,048,576k / 1024k/M = 1024MB

The dd's came back with wall clock times of 17.1 seconds and 18.85
seconds.  So the entire operation took a total of 18.85 seconds to read
1024MB of data.

1024MB /18.85sec = 54.3MB/sec


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