Add a SSD to an existing setup with ZFS, partially as root and partially as ZFS cache


Nov 26, 2018
I have been searching for articles on moving the system root to another volume, can't find any useful.

and as well i am considering if i could move an existing proxmox system to a new SSD.

Current setup:
4 HDDs as ZFS size 7T.
- Proxmox is setup on this
- and all VM hdd images are on this.

Change setup to be:
new SSD 250GB
  • 2 partitions
    • Partition 1 (maybe 32GB): Proxmox system moved to this
    • Partition 2 (rest): setup as Cache to the 7T ZFS.
existing 7T ZFS (from the 4 existing HDDs)

1. would this be a good setup?
2. anyone could feed me some steps/references?
1. would this be a good setup?

You will build a single point of failure if you move your already "raided" PVE setup to one "unraided" disk. I would not recommend that.

2. anyone could feed me some steps/references?

L2ARC is unfortunately not a mighty "get-fast"-switch so that you have to consider your current setup (RAM mainly) and often results in a slower system. Most ZFSs gain more performance by using a SLOG, not a L2ARC. To get ZFS speed, add more RAM and/or more vdevs. I suppose you use a RAIDz1 on the 4 disks or are you already using a stripped mirror? If you can tolerate less space, use two vdevs, because one vdev does perform worse than two. The reads/writes are spread across vdevs so with only one vdev, you will have only the performance from one drive.


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