Proxmox VM Hardware

[Ma907xb]

I'm new to IT and programming, but am excited to get into the field. It's my understanding you need 3 physical servers to setup a High availability cluster. 3 Nodes. Is 3 adequate to setup a cluster? Do I actually need 4 physical servers?

I'd like to setup a test cluster network with approx 60 VMs. I'm in the process of ordering 3 refurbished models from server monkey. I'd like to get this all setup using proxmox VE. Here is my setup.

1 x Dell PowerEdge R610 6-Port Chassis
1 x 2.93 GHz Hex-Core Intel Xeon Processor with 12MB Cache -- X567
1 x 32GB Memory Upgrade Kit (4x8GB) 2RX4 PC3-10600R
1 x PERC 6/i 256MB BBWC Lvl 0-60 INT RAID
1 x 300GB 10K RPM SAS 2.5" Dell Hard
1 x iDRAC6 Enterprise
1 x On-Board Quad Port 1GbE LOM
1 x Dell Intel PRO/1000 VT Quad-Port Gigabit Ethernet Network Interface Card
1 x (2) Dell 717 Watt PSU
1 x Dell SATA DVD-ROM 12.7mm Optical

Is this setup adequate to host 20 VMs running Ubuntu 18.04 per node?

 

[sb-jw]

It depends on your requirements. You need to know how many space, Ram and CPU is needed.
For HA three nodes are enough, you need a quorum, so you need an uneven amount of nodes.

Normally, I would say the CPU is enough. Thanks to KSM it might be possible that 32GB RAM are enough too. But store the OS and the VMs on a single disk might be a big problem. If every VM will use 5GB space and you will create 20 of them, then you need 100GB space. But the performance might not be enough.

Keep in mind, a dual socket system which runs only with one CPU can get unstable, this is not designed to run with only one CPU. So it's better to choose a lower CPU e.g. Quad core and install two of them.

 

[Craig St George]

Yes a lot depends on the VM;s and what they will be doing
e.g do you have an idea of the number of vcpu per VM and the RAM

for example if you have 20 VM per server and they are 2 GB ram and 1 VCPU you would need
40 GB RAM and 20 VCPU luckily you can over provision the RAM AND Physical CPU
Ram about 1.5 Times so if you have 32GB you have about 48 GB ram but the hypervisor also needs some ram
you have 6 Core CPU so 12 if you use hyper-threading and you need 20 but CPU can over-provision at 1:5 so no problem there

But once again you really need an idea on the amount or RAM and VCPU you need I would say you don't have enough RAM

Then on the HA what type of storage were you planing ? you need some shared storage. Proxmox has Ceph built in and it works fine but for every OSD ( disk you need 1 GB ram ) plus some CPU power and the other parts also need CPU and RAM


From the hardware you have you could use CEPH with the 610 but since you only have 1GB network then spinning disks will be the way to go

I have a lab setup with DELL 810 and dual CPU and 64 GB ram and CEPH on spinning disks it works fine for that and I have about 15 VM's on a node but they are not under much use. Our production systems have like 384 GB ram and have about 30 VM's each and a lot more CPU cores

 

[Ma907xb]

I appreciate the information this helped me quite a bit. I've been studying the correct setup.

I still struggle with understanding how to make a decision on a network card?

How do I make the best decision on what network card to purchase?

There would be one open port per VM.

Each VM would need a public static IP.

Even a push in the right direction would help me out.

Thank you Much!

 

[Ma907xb]

Just trying to get an answer. Thanks for taking the time.

 

[Stoiko Ivanov]

You don't need one network-card per guest (just to be sure) - this usually works via a bridge where each VM has it's virtual interface connected.
Depending on your workload and what you try to do with it 1G interfaces (which the servers you described already have) can be enough:

1 x Dell Intel PRO/1000 VT Quad-Port Gigabit Ethernet Network Interface Card

For ceph you need at least 10g for a decent performance - see the benchmark-paper https://forum.proxmox.com/threads/proxmox-ve-ceph-benchmark-2018-02.41761/

I would say - start with the Network cards you have in the servers and upgrade if you hit a bottleneck

Also make sure to update the firmware/bios/... of the servers to the latest available version - since this tends to cause problems.

Hope this helps

 

[Ma907xb]

Thank you very much. This is good information. I will continue posting if i have any further questions.