v !!! POST-MIGRATION EDIT !!! v
I shrunk the LVM partition by 5000 MiB and just ran dd overnight. I had to shuffle my boot-order around a bunch to find the one partition that would boot properly but it all just works.
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v !!! ORIGINAL POST !!! v
Hi! My Proxmox machine has 3 disks (see pic). I wish to migrate sdc to a 2TB SSD. I have LXCs on all drives and I would really like to avoid having to restart from backups. I don't have any special configuration on my proxmox, it's pretty clean and basic.
Is it safe to simply dd the old disk to the new one? I can't find an explicit answer to this question that doesn't also have a lot of other variables not relevant to me.
If not, what else can I do?
There's nothing wrong with using DD for this, but unless you're sure of the geometry of the new SSD, you may run into issues. The size of your new SSD needs to be exactly the same size or larger to fit the existing partitions of sdc since you'd be doing a block copy. Get a slightly larger drive to be safe and you'll be fine.
Honestly, DD is hard mode for this. Use a cloner that checks these things or shrinks partitions beforehand to prevent issues if you decide to go with a 2TB SSD.
Couldn't I just shrink a partition myself? I could clone the LXCs to the 4TB drive and just shrink the LVM partition significantly. DD the disks, recreate the LVM on the new SSD and move em back, right?
Using a larger disk isn't an option, unfortunately. I don't have that kind of money.
Yeah, you can do that as well. Just mentioning that DD isn't the simplest way to achieve what you want.
It might not be, but I am intimately familiar with it. It's proxmox itself that's the wildcard here. I will shrink the LVM and then DD it to the new disk.