Kernel 4.19 on proxmox

[Morbious]

Recently I installed kernel 4.19 from Ubuntu and then I recompile zfs - everything without any proxmox patches .
So far everything is running smooth but I'm wandering what I lost using ubuntu kernel instead of proxmox.
What are the disadvantages of such a solution?
The reason why I did it is that native proxmox kernel couldn't bare with backup/restore operation on my machine (thin-lvm). Each time I did it VM machines freezing for a moment of restore.

 

[t.lamprecht]

What are the disadvantages of such a solution?

You're running a completely untested setup, not that the kernel itself is untested, but the combination of it and our stack. If you run into problems you're on your own, which may be OK for you but for most people it isn't.
E.g., you could break live migration. Also, the single ubuntu 4.19 kernel available is the one from the upcomming 19.04 "Disco" release, which is currently not intended for production use.
You need to frequently recompile on the newest release, as else you risk running a system where exploits are known against, which can be problematic in a hypervisor environment where you run (possible) hostile VMs and CTs.

That said, if it works for you, you know what your do and frequently update your kernel + test it before rolling it out to your production systems it just may also be all fine for you.