Comment 16 for bug 1746630

Tested according to https://bugzilla.redhat.com/show_bug.cgi?id=1339963#c11:

1. prepare a RHEV setup: one Engine host, one virtualization host, one storage host (so three different hosts).
2. make sure to set storage as shared (default) over NFS
3. provision and run one (or more) VM(s). make sure the VM has 1+ disks over NFS
4. kill the storage, either with iptables or physically (shutdown, disconnect)
5. wait random amount of time, I recommend 2+ hours to get a good chance to recreate the conditions
6. verify Vdsm thread count is NOT growing unbounded, but stays constant.
7. In the scenario which highlighted the bug, the Vdsm thread count was growing over time in the hundreds. We are of course taking corrective action at Vdsm level to prevent this grow/leak.

vdsm Threads pool is not growing unbounded, it stays constant after few hours that the storage is unreachable while there is a running VM holding a disk on it:

[root@seal09 ~]# ps aux |grep vdsm

vdsm 19254 1.0 0.3 5564648 110240 ? S<sl 12:58 1:27 /usr/bin/python /usr/share/vdsm/vdsm

[root@seal09 ~]# grep Threads /proc/19254/status
Threads: 55

===================
Used:

vdsm-4.18.13-1.el7ev.x86_64
libvirt-daemon-driver-nwfilter-2.0.0-8.el7.x86_64
libvirt-daemon-config-network-2.0.0-8.el7.x86_64
libvirt-daemon-driver-secret-2.0.0-8.el7.x86_64
libvirt-lock-sanlock-2.0.0-8.el7.x86_64
libvirt-daemon-2.0.0-8.el7.x86_64
libvirt-daemon-driver-qemu-2.0.0-8.el7.x86_64
libvirt-daemon-config-nwfilter-2.0.0-8.el7.x86_64
libvirt-daemon-kvm-2.0.0-8.el7.x86_64
libvirt-client-2.0.0-8.el7.x86_64
libvirt-daemon-driver-storage-2.0.0-8.el7.x86_64
libvirt-daemon-driver-interface-2.0.0-8.el7.x86_64
libvirt-2.0.0-8.el7.x86_64
libvirt-daemon-driver-nodedev-2.0.0-8.el7.x86_64
libvirt-python-2.0.0-2.el7.x86_64
libvirt-daemon-driver-network-2.0.0-8.el7.x86_64
libvirt-daemon-driver-lxc-2.0.0-8.el7.x86_64
qemu-kvm-rhev-2.6.0-22.el7.x86_64
rhevm-4.0.4-0.1.el7ev.noarch
===================

Moving to VERIFIED