[Users] Creation of preallocated disk with Gluster replication

[gregoire.leroy at retenodus.net]

Hello,

I have a Gluster volume in distributed/replicated mode. I have 2 hosts.
When I try to create a VM with a preallocated disk, it uses 100% of the 
available CPU and bandwidth (I have 1 Gigabit network card).
The result is I can't even create a preallocated disk because the engine 
detects a network failure.

I get that kind of messages in /var/log/messages :
"
Jan  2 14:13:54 localhost sanlock[3811]: 2014-01-02 14:13:54+0100 167737 
[3811]: s4 kill 21114 sig 15 count 1
Jan  2 14:13:54 localhost wdmd[3800]: test failed rem 51 now 167737 ping 
167718 close 167728 renewal 167657 expire 167737 client 3811 
sanlock_ef4978d6-5711-4e01-a0ec-7ffbd9     cdbe5d:1
"

And that in the Ovirt Gui :
"
2014-janv.-02, 15:35 Operation Add-Disk failed to complete.
2014-janv.-02, 15:35 Storage Pool Manager runs on Host HOST2 (Address: 
X.X.X.X).
2014-janv.-02, 15:35 Invalid status on Data Center GlusterSewan. Setting 
Data Center status to Non Responsive (On host HOST2, Error: done).
2014-janv.-02, 15:35 State was set to Up for host HOST2.
2014-janv.-02, 15:33 Used Network resources of host HOST2 [98%] exceeded 
defined threshold [95%].
2014-janv.-02, 15:33 Add-Disk operation of test_Disk1 was initiated on 
VM test by admin at internal.

I understand that the creation of a 10 Go disk image generates a lot of 
traffic, but is there a way to limit it so that it doesn't have an 
impact on the production ? Furthermore, Why does it use so much CPU 
ressources ? I can see on my monitoring graph a big peak of CPU usage 
when I launched the operation (probably until 100%).

Thank you,
Regards,
Grégoire Leroy