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Re: [Xen-users] performance problems

  • To: xen-users@xxxxxxxxxxxxxxxxxxx
  • From: "Eric S. Johansson" <esj@xxxxxxxxxx>
  • Date: Wed, 30 Mar 2005 13:49:15 -0500
  • Delivery-date: Wed, 30 Mar 2005 18:49:31 +0000
  • List-id: Xen user discussion <xen-users.lists.xensource.com>

more info.  Don't know if it means anything.

Eric S. Johansson wrote:

running a chgrp -R over a series of directories on an LVM partition and I noticed that it was taking forever. So I ran vmstat (sorry about the line wrapping) and found that it was spending roughly 99 percent to 100 percent of the time waiting for (disk??) io.

I changed to a chgrp -Rv and what became apparent is that searching directories seem to cause a problem. This is using the reiserfs filesystem.

whenever the system was displaying the results of chgrp, the wait time would drop to under 70 percent and frequently around 50. As soon as the display of actions stopped and it was working on the disk, it would go back to 100 percent wait time.

my expectation is that the system cued up requests for the network and spent more time sending data than waiting for data. Contrast that with the disk activity which is high probability all wait time (IDE on dedicated controller)


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