High CPU Usage During File Copy

puntoboy

New Member
Apr 11, 2024
16
2
3
Hello,

I'm seeing a strange issue when copying a file via the shell from a mounted CIFS share (on an external NAS) to the local ZFS Pool. It hammers the CPU and causes high CPU usage in the VMs on the host causing them to hang.

You can see one of the VMs that's affected below, hitting 245% CPU usage when the copy starts, if I stop the copy it returns to normal. At first I thought it was because the processes were sharing the same CPU cores, but as you can see, they are not.

1720001214178.png


CPU is a 20 x Intel(R) Xeon(R) CPU E5-2640 v4 @ 2.40GHz (1 Socket) so not the more modern and up to date CPU, but copying a file shouldn't do this, should it?

Any idea where to start with this?
 
Hello,
what is your (samba, cifs) Network speed?
how big is the Filesize?
How is you ZFS Poll designt?
HDD, SSD or all of that?

10GBe
60GB
RAIDZ1
4 x 4TB HDD

I'm not expecting the transfer to be fast, but I wasn't expecting it to hammer the host so badly.
 

About

The Proxmox community has been around for many years and offers help and support for Proxmox VE, Proxmox Backup Server, and Proxmox Mail Gateway.
We think our community is one of the best thanks to people like you!

Get your subscription!

The Proxmox team works very hard to make sure you are running the best software and getting stable updates and security enhancements, as well as quick enterprise support. Tens of thousands of happy customers have a Proxmox subscription. Get yours easily in our online shop.

Buy now!