[SOLVED] Advice for new hardware

[Thomas Plant]

Hello all,

we will buy new hardware for our migration from XenServer to Proxmox and need some advice/recommendation.

First are AMD Epyc CPUs an alternative to Intel for Proxmox? Are there compatibility issues?
Will be an two AMD Epyc 7351, 2.40 Ghz 16 Core or two Intel Gold 2,20 Ghz 14 Core.
The system itself will be probably a 24 bay, 2,5" Supermicro chassis, with an LSI 9300-8i HBA. No problems there I presume, LSI has always worked here with Debian. Any known issues?
HDDrives will be 10.000 rpm 2,5" 1.2TB in RAID10. We will host KVM VMs, aprox. 30 for every host. They have very mixed workload, from simple Webhosting to a mailserver, MySQL etc. Very difficult to tell how much IO/s the make currently, as our old storage has no statistics about this.
I was thinking to add a 3,2 TB NVMe PCIe (5 DWPD) for SLOG and L2ARC, partition it to 64GB for SLOG and the rest for L2ARC, or for local storage the SLOG should be bigger?
With KVM are the writes all 'sync'? Or do I have to set the zvols Proxmox creates manually to 'sync=always' to use the NVMe Log?

Kind regards,
Thomas

 

[wolfgang]

Hi,

First are AMD Epyc CPUs an alternative to Intel for Proxmox?

Yes

Are there compatibility issues?

The only known problem is Installation of windows does not work straight.
You have to disable msr in the KVM module if you like to install windows10 or server2016.

Any known issues?

Broadcom former LSI HBA works great with Linux.

I was thinking to add a 3,2 TB NVMe PCIe (5 DWPD) for SLOG and L2ARC, partition it to 64GB for SLOG and the rest for L2ARC, or for local storage the SLOG should be bigger?

I think this is too much and L2ARC must be used with care.
see https://forum.proxmox.com/threads/suggestions-for-hw-setup.52562/#post-243339

With KVM are the writes all 'sync'?

KVM will write as the application requested it, but you can force sync over the HDD settings.

Consider using enterprise SATA SSD instead of SAS HDD the price should be near the same.

 

[Thomas Plant]

Many thanks for the infos,
great tip using SATA SSDs, didn't think about it. Will 'google' how to disable 'msr'.....

regards,
Thomas

 

[Thomas Plant]

No so easy finding informations about these 'msr' things ;-)

is this the right thing to do?
edit '/etc/modprobe.d/kvm.conf ' and add the line 'options kvm ignore_msrs=1'

or can I disable it per VM?

 

[wolfgang]

This is correct.

or can I disable it per VM?

You can not set it on VM level only Global.

In the next major kernel upgrade, this problem should be fixed and it will work without this workaround.

 

[Thomas Plant]

Ok. Thanks.

 

[Toxik]

Is this fixed in kernel 5.0.15-1-pve? So there is no reason to not use AMD Epyc based servers with Proxmox?

 

[s.Oliver]

Is this fixed in kernel 5.0.15-1-pve? So there is no reason to not use AMD Epyc based servers with Proxmox?

+1