qm clone takes a lot more time than usual

O

oknet

Member
Oct 13, 2022
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I have two Proxmox ve hosts

qm-cloning a virtual machine (50 GB VM on one system and 40 GB VM on the other ) it takes about 10-12 minutes to complete cloning, where it took a pair of minutes initially on both systems (one uses HDD , the other SSD no relevant differences) .
Monitoring qm clone , there are moments where it takes few seconds per one GB copy, other where it stucks a minute for a single GB
No difference if source VM is running or not .
What's the issue ? What to check ?
 
What are the make and model of your drives? QLC SSD drives are known to become slower than HDD once they become full or during prolonged writes.
 
A system uses two 500GB Samsung 870 evo ssd
The other one a pair of 4TB WD red nas hdd
Both on zfs
Both VMs are the same voip pbx software.
As wrote , weird thing is the long cloning time not along all process but slowing down in particular spots.
There are moments in which 5GB are processed in a bunch of seconds, as well as it stucks on 1GB for 100 seconds….
 
Last edited:
oknet said:
A system uses two 500GB Samsung 870 evo ssd
The other one a pair of 4TB WD red nas hdd
Both on zfs
Both VMs are the same voip pbx software.
As wrote , weird thing is the long cloning time not along all process but slowing down in particular spots.
There are moments in which 5GB are processed in a bunch of seconds, as well as it stucks on 1GB for 100 seconds….
Click to expand...
WD Red's are often SMR drives that cannot handle sustained writes and give issues with ZFS. WD introduced Red Plus label for drives actually suitable for NAS (which people still disagree with but that's a different discussion). What model are they exactly? Maybe that's why writes are quickly buffered until buffers are full and only slowly written to disk, which would explain what you are seeing.
 
My mistake...I was thinking to another proliant microserver I own...o_O

The one running proxmox discussed here use a pair of WD red SSd : WDS500G1R0A-68A4W0
 
oknet said:
My mistake...I was thinking to another proliant microserver I own...o_O

The one running proxmox discussed here use a pair of WD red SSd : WDS500G1R0A-68A4W0
Click to expand...
Maybe the same story? At least they are not QLC but consumer SSDs don't handle sustained writes (once the memory and SLC buffer runs out) very well, especially when getting full. Do you trim the drives regularly? Check the wear and writes via SMART, as they support only 191GB per day for the duration of the warranty (1 year, 2 maybe?).
 
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