Re: [PVE-User] Hardcoded startup RAM for QEMU memory hotplug

["DERUMIER, Alexandre via pve-user" <pve-user@lists.proxmox.com>]

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From: "DERUMIER, Alexandre" <alexandre.derumier@groupe-cyllene.com>
To: "jan.pechek@daktela.com" <jan.pechek@daktela.com>
Cc: "pve-user@lists.proxmox.com" <pve-user@lists.proxmox.com>
Subject: Re: [PVE-User] Hardcoded startup RAM for QEMU memory hotplug
Date: Tue, 13 Jan 2026 10:46:22 +0000
Message-ID: <5bbaa0560a21d096485f25b759110a3b3166ff48.camel@groupe-cyllene.com>


>>Hi,
>>Looking at the code, it's 1024MB * the number of sockets, so adding
>>sockets might be workaround. Thanks for the idea. Another workaround
>>might be to simply disable memory hotplug before leapp.
>>The kernel option "memhp_default_state=online" also works. However, I
>>think the ability to configure the startup RAM size in Proxmox would
>>be nice.

I had sent some patches 2 years ago with a rework of the code + virtio-
mem implementation, where 4G was used at minimum static (because
unhotplug is not working fine under 4G).

If I have time, I'll try to rework on it again.




On Thu, Jan 8, 2026 at 4:21 PM DERUMIER, Alexandre
<alexandre.derumier@groupe-cyllene.com> wrote:
> hi currently no, but it's related to the number of cpu sockets of the
> vm. (it's 512mb by socket if I remember correctly).
> 
> so, you can try a vm with 4 sockets.
> 
> 
> you can also add "memhp_default_state=online" to kernel boot option,
> it
> should auto enable the hotplug memory dimm when kernel boot
> 
> 
> -------- Message initial --------
> De: Jan Pechek via pve-user <pve-user@lists.proxmox.com>
> Répondre à: Proxmox VE user list <pve-user@lists.proxmox.com>
> À: pve-user@lists.proxmox.com
> Cc: Jan Pechek <jan.pechek@daktela.com>
> Objet: [PVE-User] Hardcoded startup RAM for QEMU memory hotplug
> Date: 08/01/2026 14:43:34
> 
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