Tips on how to manage load after reboot

[SamTzu]

I have been trying to spread the load so to speak after host reboots.
Greatest problem now seems to be MariaDB.
When all LXC containers start Maria causes very high IO delay on the host.
Any idea how to fix that or spread that around (without startup delay)?

 

[Folke]

Hi,
when you go to Start/Shutdown order under Options in your VM, you can set a startup delay. Our documentation has an explanation how the values are interpreted [0].

[0] https://localhost:8006/pve-docs/chapter-pct.html#pct_startup_and_shutdown

 

[gfngfn256]

Hi,
when you go to Start/Shutdown order under Options in your VM, you can set a startup delay. Our documentation has an explanation how the values are interpreted [0].

Quote of OP:

Any idea how to fix that or spread that around (without startup delay)?

You are probably going to have to limit that (somehow) within the LXC (Maria DB) itself. There is probably a way - I'm just not familiar with it.

 

[Folke]

Quote of OP:

Whoops, overlooked that.

You are probably going to have to limit that (somehow) within the LXC (Maria DB) itself. There is probably a way - I'm just not familiar with it.

You might be able to limit the IO via cgroups, but there is one big limitation. If you are using ZFS, this method is out, since it isn't integrated well enough into the Linux kernel to be affected by the cgroup limits. I'm not sure about other file systems, but AFAIK, all the common ones that ship natively with the kernel should work. You'll want to set io.max which you can find for each container at /sys/fs/cgroup/lxc/<vmid>/io.max [0].

[0] https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html#io-interface-files