Thanks Ruben.
I've realised that lower performance takes place each time a new VM is
in PROLOG status or when I create/clone an image. I guess all that is
related to disk access. As a testing purpose, I've cloned an image and
executed iotop in the server where OpenNebula and NFS Server are running.
This is a sample output:
PID PRIO USER DISK READ DISK WRITE SWAPIN IO> COMMAND
3238 be/7 oneadmin 1783.88 K/s 1783.88 K/s 0.00 % 93.98 % cp -f
/var/lib/one/datastores/1/9fedfe0d5cb02961~ne/datastores/1/72da3ba9d86fdc573b944c03253561ae
Sometimes, there is another process (flush-147:0) with an important IO
usage:
PID PRIO USER DISK READ DISK WRITE SWAPIN IO> COMMAND
8028 be/4 root 1358.87 B/s 7.96 K/s 0.00 % 4.15 % [flush-147:0]
How could I set an "ionice -c 3" to that "cp" command? I would like to
do it in a global and persistent way so that future cp actions (due to
creation or cloning of a VM or an image) have a lower ionice, not just once.
Perhaps, I should set ionice in the driver configuration "exporting" a
new global variable in /etc/one/defaultrc in the same way as the
priority, shouldn't I? But, how do I configure ionice to interact with
the proper driver?
Thanks for your help.
Carlos.
On 11/13/2012 11:51 AM, Ruben S. Montero wrote:
Hi
OpenNebula drivers are the piece of software that deals with the
underlying subsystems. Each driver starts a new thread/process for
each operation that should inherit the driver priority.
If you take a look to /etc/one/defaultrc, you can change the CPU
priority assigned to the drivers. It defaults to 19, the least
favorable to the process. You may want to try to use sets other io
scheduling algorithm with ionice, or the blk module of cgroups.... or
any other tool to adjust the I/O priority of a process.
Cheers
Ruben
On Mon, Nov 12, 2012 at 5:59 PM, Carlos Jiménez
<[email protected] <mailto:[email protected]>> wrote:
Hi all,
I have a server running OpenNebula 3.8 and acting as NFS server
for storaging with another host (running KVM and acting as a NFS
client for the storage). I have one VM running and then I try to
create another VM using Sunstone. Then, the running VM reduces its
performance while the creation of the new VM takes places. I guess
OpenNebula I/O processes on the shared disk have better
priority/nice/ionice than disk access of the already running VM.
The question is: Is there any way to control it so running VMs
don't decrease their performance? How do you reduce
priority/nice/ionice of the creation of the new VMs?
Thanks in advance,
Carlos.
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Ruben S. Montero, PhD
Project co-Lead and Chief Architect
OpenNebula - The Open Source Solution for Data Center Virtualization
www.OpenNebula.org <http://www.OpenNebula.org> |
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