From: Gregory (Grisha) Trubetskoy (grisha_at_ispol.com)
Date: Fri 01 Apr 2005 - 22:25:41 BST
I would also keep measurements of CPU ticks used. Since IO requires CPU
cycles - is it possible that a CPU sched_hard indirectly limits IO just as
On Fri, 1 Apr 2005, Matthew Nuzum wrote:
>> On Thu, Mar 31, 2005 at 09:22:10PM -0600, Matthew Nuzum wrote:
>>> I think I can create a test case for this. I have a server that is not
>>> currently running any vserver stuff that will be ok with a reboot now
>> sounds good, please try to get 184.108.40.206 working there,
>> because it already contains some blkio accounting
>> and it would be very interesting to monitor those
>> values ... (maybe with rrdtools)
> I'm still doing my month-end backup, but when that's done I'll start
> installing the vserver 220.127.116.11.
> Here is the test case that seems most logical to me, but advice on how to
> actually do concrete tests would be useful.
> 1. Create two vservers (vsa and vsb), start both.
> 2. In vsa start some heavily i/o intensive operation
> 3. In vsb try to do some tasks and notice how much i/o bandwidth I have
> Alternative plan:
> 1. Create 1 vserver and start it
> 2. In the vserver, start some heavily i/o intensive operation
> 3. In the host server try to do some tasks and notice how much i/o bandwidth
> I have available
> 4. After step 2 completes, in host server start a heavily i/o intensive
> 5. In vserver, try to do some tasks and notice how much i/o bandwidth I have
> I have two ideas on heavily i/o intensive operation
> 1. I have a database with 35 million records. Doing any aggregate function
> such as max() requires several sequential scans and takes a significant
> amount of time.
> 2. Preparing my month end backup requires copying 13 GB of data.
> Any other suggestions?
> I have only subjectively noticed a dramatic decrease in server performance
> when a vserver is performing i/o intensive tasks. How can I objectively
> measure and produce concrete numbers?
> Matthew Nuzum <matt_at_followers.net>
> www.followers.net - Makers of "Elite Content Management System"
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