On Fri, Apr 01, 2005 at 12:23:00PM -0600, 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 > > and > > > then. > > > > sounds good, please try to get 1.9.5.5 working there, > > because it already contains some blkio accounting > > and it would be very interesting to monitor those > > values ... (maybe with rrdtools) > > > > TIA, > > Herbert > > I'm still doing my month-end backup, but when that's done I'll start > installing the vserver 1.9.5.5. > > 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 > available. > > 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 > operation > 5. In vserver, try to do some tasks and notice how much i/o bandwidth I have > available > > 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? > > Question: > 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?
there are two 'aspects' of what you 'experience' as performance here. first the increased latency when doing I/O (which is the result of several I/O transactions already going on when you do whatever you do), and the decreased throughput (which IMHO is not really the issue here, just think 40MB/s transfer with UDMA and 4MB/s without ...) I would suggest to 'test' with different I/O schedulers activated, because I think that the default I/O scheduler might be sub-optimal for vserver-type I/O loads anyways ... TIA (for testing) Herbert > -- > Matthew Nuzum <[EMAIL PROTECTED]> > www.followers.net - Makers of "Elite Content Management System" > View samples of Elite CMS in action by visiting > http://www.followers.net/portfolio/ > > _______________________________________________ > Vserver mailing list > [email protected] > http://list.linux-vserver.org/mailman/listinfo/vserver _______________________________________________ Vserver mailing list [email protected] http://list.linux-vserver.org/mailman/listinfo/vserver
