1 GB RAM not enough even for testing purposes

[harvie]

I had PVE 4.4 test setup with 1 GB ram and recently upgraded to PVE 5.0, it gives lots of various memory allocation errors even when there's nothing else running (no CT, no VM, no nothing).

This page
https://www.proxmox.com/en/proxmox-ve/requirements
says:
Minimum Hardware (for testing only): Minimum 1 GB RAM

I guess it's no longer true. I think you need at least 2GB of RAM. I think you should update this page.
It does not even start all proxmox ve daemons and logs errors like:

failed: open3: fork failed: Cannot allocate memory at /usr/share/perl5/PVE/Tools.pm line 429

or

Can't load '/usr/lib/x86_64-linux-gnu/perl5/5.24/auto/PVE/RADOS/RADOS.so' for module PVE::RADOS: librados.so.2: cannot map zero-fill pages at /usr/lib/x86_64-linux-gnu/perl/5.24/DynaLoader.pm line 187

and lots of others directly in web ui

 

[wolfgang]

Hi,

a fresh installed PVE 5.0 needs without any extra services 750MB without zfs.
ZFS need much more.

 

[jim.bond.9862]

did you install a new or upgrade 4.4 to 5 ?
in all my tests I could never upgrade, I had to reinstall a new. otherwise got all sorts of errors and issues. but 1GB is never enough. especially if you use ZFS. the system needs at least 600M to 800M to itself.

 

[harvie]

you know what is funny? I have two testing servers with PVE 5.0, one has 8GB ram, one has 1GB. They both use like 800M of memory, however the one with 1GB has problems operating. It seems to me that there are some burst of momentary needs of memory which leads to allocation failures. Hah, which leads me to finding that i don't have swap on the testing machine :-D I deleted it because i needed some extra partition for experimenting with storage options and forget to setup it again.

OMG i also found that i have mem=1GB in grub.cfg, because i was doing some storage tests and i wanted to prevent caching as much as possible. Which pretty much solves my problems, however this was not point of this thread. Let's go to conclusion:

It's not possible to run PVE 5.0 using 1GB RAM without swap. It's not even possible to upgrade from 4.4 to 5.0, because it will fail not being able to restart services during upgrade.

 

[wolfgang]

It's not possible to run PVE 5.0 using 1GB RAM without swap. It's not even possible to upgrade from 4.4 to 5.0, because it will fail not being able to restart services during upgrade.

This can be true but this is not a common setup and we can't test all possibility you could set up.

 

[Trogvar]

Had same trouble after Proxmox upgrade from 3.x to 4.x and then to 5.x.
Server been in production for a long time and I didn't want to brake the system while update (and this happened), so i waited till migration to new hardware.

So after upgrade I've got same error:
Can't load '/usr/lib/x86_64-linux-gnu/perl5/5.24/auto/PVE/RADOS/RADOS.so' for module PVE::RADOS: /usr/lib/x86_64-linux-gnu/librados.so.2: undefined symbol: _ZN5boost6random13random_deviceC1ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE at /usr/lib/x86_64-linux-gnu/perl/5.24/DynaLoader.pm line 187, <DATA> line 755.

And so on.. Cluster didn't start.

After several hours came to solution:

add deb http://download.proxmox.com/debian/ceph-luminous stretch main to sources and apt-get update & apt-get upgrade

System started and work like a charm having all VM working.