Bad performance when import to lvm device or moving a powered of VM to lvm

ThomasGlanzmann

New Member
Nov 24, 2023
2
0
1
Hello,
we noticed that moving a powered off machine or importing a disk using qm importdisk <id> </path/to/vmdk> <storage> to a lvm on SAN is slow. When running iostat -xm 2 I observed that proxmox issues 20k IOPS with an avg. I/O size of 4 KB. As result the import speed is something around 76 MB/s to a NetApp AFF A150 connected using FC, iSCSI or NVMe/TCP. However when the VM is powered on, an avg I/O size of 1 MB is used resulting in approx 500 MB/s. It would be nice if someone could fix this code path. Also when offline or online moving the vm disk from lvm to another storage an I/O size of 1 MB/s is used which results in good throughput (1 GB - 2 GB/s).

Cheers,
Thomas
 
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