RAM Upgrade on Proxmox Server

[Raid007]

Hey all,

I'm planning to upgrade my RAM from 128GB to 256GB on a Proxmox server.
The motherboard supports the upgrade, but are there any Proxmox-specific considerations I should be aware of?

Will the additional RAM be recognized immediately after installation and a reboot?

Thanks!
Raid007

 

[LnxBil]

The motherboard supports the upgrade, but are there any Proxmox-specific considerations I should be aware of?

No, unless you changed something yourself (e.g. limiting ZFS ARC)

Will the additional RAM be recognized immediately after installation and a reboot?

Yes, instantly.

 

[Raid007]

No, unless you changed something yourself (e.g. limiting ZFS ARC)

I am using a ZFS Pool but with the default settings (nothing changed so far). So currently 64 GB of 128 GB is used for caching. Will it grow to 128 GB/256 GB or stay at 64 GB. The size of the ZFS is "only" 8 TB so I would prefer if the size will stay to 64 GB.

 

[UdoB]

Will it grow to 128 GB/256 GB

Yes.

Please follow https://pve.proxmox.com/wiki/ZFS_on_Linux#sysadmin_zfs_limit_memory_usage to set a specific limit.

Best regards

 

[Raid007]

Okay. Thank you!
Does anyone a good advice how much Cache for 8 TB ZFS Pool makes?

Is there anything else which could be a problem caused by the ram upgrade? Has anyone made bad experencices?

 

[LnxBil]

Does anyone a good advice how much Cache for 8 TB ZFS Pool makes?

No, because "it depends". As always: the more cache the better ...

Is there anything else which could be a problem caused by the ram upgrade? Has anyone made bad experencices?

There are some drawbacks:

• Booting (BIOS post) will take more time
• memory fragmentation can be worse
• if memory modules are not properly aligned with channels, your system may be slower
• if memory modules are not compatible enough, you may have slower memory speed

 

[Raid007]

Okay - thank you!
The server is not really old and I will add the same memory, which is still on the market.

So best I can do is to try it out and hope for the best.

 

[LnxBil]

The server is not really old and I will add the same memory, which is still on the market.

I just want to say: that does not mean that it works. If you e.g. occupy each slot and the memory is of the wrong rank type, it will not work. I had this in the past. It's not as easy as just plugging in/doubling stuff. Just keep that in mind.

So best I can do is to try it out and hope for the best.

In the end ... yes

 

[Raid007]

In the end ... yes

Yes, that's exactly the problem. Anything unexpected can always happen. In the end, it's just a matter of trying and either everything works out or you go through hell. I'm hoping for the best and hopefully, you'll keep your fingers crossed for me

 

[LnxBil]

you'll keep your fingers crossed for me