On lun add/remove all iscsi sessions are restarting

R

redtex

Renowned Member
Sep 13, 2012
28
1
68
Hi, I'm using scst v3.0.2 target with Proxmox VE 3.4

When I add/remove iscsi LUN, whole VM's which connected to this
target stops it's disk activity, and seems to be forced to re-connect to
target. It's not a problem when you have 3-5 luns, but when target have
more than 100 luns this re-connect sequence takes about 10 minutes Is
it possible, to change such behavior ?

SCST team's answer on such request follows:

Please ask the Proxmox maintainers to modify how SCSI unit attention conditions are handled in Proxmox. SCST submits a "REPORTED LUNS DATA HAS CHANGED" to the initiator after a LUN has been added or removed. If the initiator receives that UA it should rescan LUNs instead of disconnecting and reconnecting. See also http://www.t10.org/lists/asc-num.htm for a complete list of unit attention conditions.

# pveversion -v
proxmox-ve-2.6.32: 3.3-147 (running kernel: 2.6.32-37-pve)
pve-manager: 3.4-1 (running version: 3.4-1/3f2d890e)
pve-kernel-2.6.32-20-pve: 2.6.32-100
pve-kernel-2.6.32-19-pve: 2.6.32-96
pve-kernel-2.6.32-28-pve: 2.6.32-124
pve-kernel-2.6.32-25-pve: 2.6.32-113
pve-kernel-2.6.32-37-pve: 2.6.32-147
pve-kernel-2.6.32-17-pve: 2.6.32-83
pve-kernel-2.6.32-34-pve: 2.6.32-140
pve-kernel-2.6.32-11-pve: 2.6.32-66
pve-kernel-2.6.32-18-pve: 2.6.32-88
pve-kernel-2.6.32-23-pve: 2.6.32-109
lvm2: 2.02.98-pve4
clvm: 2.02.98-pve4
corosync-pve: 1.4.7-1
openais-pve: 1.1.4-3
libqb0: 0.11.1-2
redhat-cluster-pve: 3.2.0-2
resource-agents-pve: 3.9.2-4
fence-agents-pve: 4.0.10-2
pve-cluster: 3.0-16
qemu-server: 3.3-20
pve-firmware: 1.1-3
libpve-common-perl: 3.0-24
libpve-access-control: 3.0-16
libpve-storage-perl: 3.0-31
pve-libspice-server1: 0.12.4-3
vncterm: 1.1-8
vzctl: 4.0-1pve6
vzprocps: 2.0.11-2
vzquota: 3.1-2
pve-qemu-kvm: 2.1-12
ksm-control-daemon: 1.1-1
glusterfs-client: 3.5.2-1
 
dietmar said:
We use open-iscsi, so I guess that needs to be handled there?
Click to expand...

hmm.... I don't think so, because when I run VM i see this:

# px ax | grep kvm
928215 ? Sl 16:28 /usr/bin/kvm -id 219 -chardev socket,id=qmp,path=/var/run ........ -drive file=iscsi://192.168.107.22/iqn.2005-05.com.sdsys2:sas-15k/33,if=none,id=drive-virtio0,aio=native,cache=none,detect-zeroes=on .........

the expression -drive file=iscsi:// indicates, that qemu uses libiscsi, not open-iscsi
 
dietmar said:
Yes, in this case it is libiscsi.
Click to expand...

So, I'm asking you, as maintainers of libiscsi:

To modify how SCSI unit attention conditions are handled in Proxmox. SCST submits a "REPORTED LUNS DATA HAS CHANGED" to the initiator after a LUN has been added or removed. If the initiator receives that UA it should rescan LUNs instead of disconnecting and reconnecting. See also http://www.t10.org/lists/asc-num.htm for a complete list of unit attention conditions.
 
dietmar said:
You better ask that on the libiscsi mailing list. see

https://github.com/sahlberg/libiscsi/blob/master/README
Click to expand...

just to help everyone understand: your answer is that this problem is not to be solved on proxmox ve side, but on libiscsi?
from the initial post, it seemed that the rtequest was <<ask the Proxmox maintainers to modify how SCSI unit attention conditions are handled in Proxmox>>..?

I'm lost

Marco
 
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