It takes several minutes to list all virtual environments using
[root@pcs1 ~]# time prlctl list -a ... real 7m50.871s user 0m1.377s sys 0m0.028s
The following messages can be found in
F /IOCommunication:393832:367005/ IO server ctx [read thr] (handle 187, sender 2): WARNING: callback took too much time: about 11923 msecs. This is absolutely incorrect! Callback must be rewritten!
There's an NFS share with virtual machines templates, mounted on the server, and it is slow in response:
[root@pcs1 ~]# time df -h /vz/vmtemplates Filesystem Size Used Avail Use% Mounted on nfs_share:/share 2.0T 1.6T 345G 83% /vz/vmtemplates real 0m39.074s user 0m0.001s sys 0m0.001s
prlctl queries the location of both virtual machines and templates, when it generates the list of virtual environments, so slow response from the NFS server leads to the delay in this procedure.
Fix the slowness of the NFS server.