From: "Alberto Treviño" <alberto@byu.edu>
To: "kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: Avoiding I/O bottlenecks between VM's
Date: Fri, 19 Sep 2008 12:53:30 -0600 [thread overview]
Message-ID: <200809191253.30228.alberto@byu.edu> (raw)
In-Reply-To: <20080919184146.GA12928@dmt.cnet>
On Friday 19 September 2008 12:41:46 pm you wrote:
> Are you using filesystem backed storage for the guest images or direct
> block device storage? I assume there's heavy write activity on the
> guests when these hangs happen?
Yes, they happen when one VM is doing heavy writes. I'm actually using a
whole stack of things:
OCFS2 on DRBD (Primary-Primary) on LVM Volume (continuous) on LUKS-encrypted
partition. Fun debugging that, heh?
In trying to figure out the problem, I tried to reconfigure DRBD to use
Protocol B instead of C. However, it failed to make the switch and both
nodes disconnected so now I have a split-brain. In try to fix the split
brain I'm taking down on one node all the VM's one by one, copying the VM
drives from one node to the next, and starting up on the other node (old-
fashioned migration). Yes, I'm having *lots* of fun! Perfect way to end
the week!
So, any ideas on how to solve the bottleneck? Isn't the CFQ scheduler
supposed to grant every processes the same amount of I/O? Is there a way to
change something in proc to avoid this situation?
--
Alberto Treviño
BYU Testing Center
Brigham Young University
next prev parent reply other threads:[~2008-09-19 18:53 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-19 17:26 Avoiding I/O bottlenecks between VM's Alberto Treviño
2008-09-19 18:41 ` Marcelo Tosatti
2008-09-19 18:53 ` Alberto Treviño [this message]
2008-09-19 19:14 ` Javier Guerra
2008-09-19 19:53 ` Marcelo Tosatti
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=200809191253.30228.alberto@byu.edu \
--to=alberto@byu.edu \
--cc=kvm@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox