DRBD stops VM til end of write

I have installed a proxmox cluster on 2 Lenovo RD340, Debian install and use MD-Raid1.
Also have a NAS Quorum connected on iscsi.

The drbd-connect is made with interated eth1 over 1 Gbit, proxmox runns on eth0.

Advertised pause frame use: Symmetric
Advertised auto-negotiation: Yes
Speed: 1000Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 1
Transceiver: internal

I have 1 VM running Ubuntu 12.04 LTS with Kerio (35 User) installed inside.
Kerio write a lot on the discs and the hole VM stops working until the write on drbd is done. :-(

101.conf:
scsi0: VM_Disk_drbdvg0:vm-101-disk-1,cache=directsync,size=75G <- sytsem
scsi1: VM_Disk_drbdvg0:vm-101-disk-2,size=550G <- kerio


resource r1 {
protocol C;
startup {
wfc-timeout 0; # non-zero wfc-timeout can be dangerous (http://forum.proxmox.com/threads/346...-configuration)
degr-wfc-timeout 60;
become-primary-on both;
}
net {
sndbuf-size 512k;
cram-hmac-alg sha1;
shared-secret "XXXXX";
allow-two-primaries;
after-sb-0pri discard-zero-changes;
after-sb-1pri discard-secondary;
after-sb-2pri disconnect;
#data-integrity-alg crc32c; # has to be enabled only for test and disabled for production use (check man drbd.conf, section "NOTES ON DATA INTEGRITY")
}
on node1 {
device /dev/drbd0;
disk /dev/md2;
address 10.1.5.31:7788;
meta-disk internal;
}
on node2 {
device /dev/drbd0;
disk /dev/md2;
address 10.1.5.32:7788;
meta-disk internal;
}
disk {
# no-disk-barrier and no-disk-flushes should be applied only to systems with non-volatile (battery backed) controller caches.
# Follow links for more information:
# http://www.drbd.org/users-guide-8.3/...sable-barriers
# http://www.drbd.org/users-guide/s-th...sable-barriers
# no-disk-barrier;
# no-disk-flushes;
# no-disk-flushes;
# no-md-flushes;
#no-disk-barrier;
}

Unfortunatelyi can't change to protocol A in a primary/primary installation. So any hints to keep the system running while write on drbd?
Or can proxmox work with primary/secondary setup?

Sytem is unuseable at the moment, if get 1 x 2,5MB Email to 3 recipients it's writing 30 MB to drbd (nmon). :-(
If system stops it not write the systemstate in kerio also and user can't do anything. 11:28 til 11:31.
kerio_stop11:28.png

I can do a ps -ax or something but not get answer to df -h or mount or somithing else who needs disc access! :-(
Any idea?

Thanks

Attached Images

• kerio_stop11:28.png (49.8 KB)