Very slow write speed and constant high I/O pressure on Proxmox

daFelix

New Member
Sep 27, 2025
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0
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Hey,
if I try to create a LXC Container on my Proxmox, it takes up to 5 minutes. The issue doesn't appear when I install a VM.

While a container is creating, the disk usage for that disk is at 100% (checked with iostat -x 1)
I also tried to write with "dd":
Code:
root@pve1:~# dd if=/dev/zero of=testfile bs=1G count=1 oflag=dsync
1+0 records in
1+0 records out
1073741824 bytes (1.1 GB, 1.0 GiB) copied, 227.09 s, 4.7 MB/s
(independent from the disk I use)

On my other node (pve2), the container only needs 5-10 seconds to install

Hardware:
I have a Proxmox Cluster with 2x HPE dl380 G9 Server.
pve1:
  • 440 GiB RAM
  • 24 x Intel(R) Xeon(R) CPU E5-2643 v4 @ 3.40GHz (2 Sockets)
  • 4x HDDs je 1TB

pve2:
  • 32 GB RAM
  • 40 x Intel(R) Xeon(R) CPU E5-2650 v3 @ 2.30GHz (2 Sockets)
  • 4x HDDs je 1TB
Both Servers run with Proxmox 9.0.9 (Kernel = pve1: 6.14.8-2-pve, pve2: 6.14.11-1-pve, could that be the problem?)

On pve1, the RAID controller passes through all disks (HBA enabled), so Proxmox has full control over them. 3 of 4 Disk are separated LVM-Thin Volumes.
1759009072044.png

I thought it could have something to do with cache, but I'm not sure..


Thank you, I'm thankful for every little idea :)