Moving host partitions to smaller drive

[Orion Pax]

Hi everybody.

I have a challange.

In my server (Dell T410, 128GB mem, and loads of disks)

I have installed proxmox on a zfs mirror raid of 2 1tb consumer ssd's and i want to move those to two smaller enterprise ssd's becauise of io delay spikes i am experiencing.
( i was unaware of these problems with consumer ssd's beforehand)

Now i have 2 pci ssd's of 784GB each and i want to move the boot and host partitions and VM to a new zfs mrirror with these two drives.

What is the best approach for this?

First i thought of leaving the host on the (old) SSD's and just moving all the VM's to the new drives.
Will that be enough to reduce the bulk of the IO delay or is it necessary to move the whole thing.

What do you think?

Moving VM harddisks is quite easy so i know how tho do that.
But migrating the whole host is something i have no clue where to start.
I am an hobbyist , working with Linux for 15 years but proxmox and zfs is quite new for me so any new insights and tips are welcome.

 

[Dunuin]

Most IO should come from your guests.

 

[Orion Pax]

Do you mean VM's and containers?

 

[Dunuin]

Jup. PVE itself writes a lot but not that much that a cheap SSD shouldn't be able to keep up, unless you also want to store your backups on the "local" storage.

Might be possible to somehow replace the disks, but I think it should be easier to just backup guests and host configs, install PVE again and restore guests and configs afterwards.

 

[Orion Pax]

I have managed to install the fusion drives (which was a pain for e newbee like me but i persevered )

Since I have two of them i want to create a mirror on which i serve all the VM's (not big storage) to keep my io from spiking.
The drives are not showing up as disks in the webgui so i followed the instructions in this post which results in two thin LV's.
But i can not move any of the existing VM disks to these LV's, nor can i create a mirror this way.

But I am new to proxmox, i have still a lot to learn about storage types.
Does anyone have a suggestion on how to approach this?

 

[Orion Pax]

I now am testing with a zfs mirror pool i created with the command-line.

 

[narrateourale]

This blog post looks pretty much like what you want to do.

 

[Orion Pax]

Thanks, seems like a complicated procedure but i will look into it.

I am now moving my vm's to the zfs mirror that is running on 2 fusion ioDrive 2 drives. Hopefully that will be enough to bring the io-spikes down.
Also it has a much higher durability than the consumer grade ssd's i have installed. (which i can now overprovision like 500% )