[SOLVED] Wrong time on cluster/windows 2022 guests

[Humay]

wrong time like 20 secs clock skew on windows servers which used local time (VIRTIO guest additions installed)
after setup ntp source its back to about 1sec

this servers use pbs for backuping daily with backup "stop" option

seems host time was right (not sure, im resync first then guest time was still 20s skew) seems only guest was skewed

uptime
15:32:26 up 12 days, 21:36, 1 user, load average: 2.28, 3.29, 3.33

can too uptime interfere with daily backup?

i think both guests were skewed but idk if they excatly same time skew

 

[_gabriel]

don't forget "stop" backup stop VM to start backup but restart VM while backup continue in background, when destination is slow, VM can slowdown (even if host is beefy), some services can be disturbed / stopped , why not indeed time.

try schedule shutdown within VM to backup fully stopped, then crontab (or better hook script) to start VM after the backup.

 

[Humay]

i switched to use ntp time to guests, VM is on NVME SSD and ZFS disks with alot of memory (around 1TB), backup target is yes a bit slow PBS VM on synology rackstation

 

[_gabriel]

try https://pve.proxmox.com/wiki/Guest_Time_drift

 

[Humay]

some say need to turn on KVM64 cpu instead of host and make use 1 socket multiple cores but skew was on 2 different guests with different host cpu settings (host and other kvm64) both was skewed 4x4 and 1x8 socket/threads
also VMWARE recommends use ntp sources for guest and disable time sync with guest for host
is this possible to disable timesync from host? on proxmox i mean

 

[Humay]

try https://pve.proxmox.com/wiki/Guest_Time_drift

is that HPET thing safe? will not ruin performance?

 

[Humay]

seems at moment it solved problem