Hey! Listen! This post is part of a series on the DeskMini H470 as a hypervisor. Check them all out!
|2022-09-07||Adding a ZFS mirror to Proxmox||Add a ZFS mirror to Proxmox|
|2022-09-02||Adding data center SSDs to the DeskMini H470||Add 2x Intel D3-S4510 to the DeskMini H470|
|2021-06-23||ASRock DeskMini H470 as a compact hypervisor||Initial post about DeskMini H470|
In my last post, I added two Intel D3-S4510 960 SSDs to my ASRock DeskMini H470 running Proxmox. I also upgraded the firmware, as well as ran some basic tests on the drives. In this post, I’ll be creating a ZFS mirror and adding it to Proxmox.
⚠️ WARNING ⚠️
- This was my first time using ZFS
- I am not a ZFS expert
- Don’t blindly follow my instructions
- Almost all of my ZFS knowledge came from this ArsTechnica article, Jim Salter’s blog, and this article.
Using the GUI, you can create the mirror and add it to Proxmox in one step. However, I’m specifically looking to add one extra thing that is not in the GUI, so I’m using the CLI.
Start by creating the mirror.
zpool create -f -o ashift=12 intel_mirror mirror /dev/disk/by-id/xxxxxx /dev/disk/by-id/yyyyyy
In the command above, it’s important that
ashift be the correct size (that’s why I had to find the sector size in the last post). It generally won’t hurt if
ashift is too big, but if it’s too small (the default is
9), there will definitely be some performance impact as the drive will do write amplification to fill a 4096B sector with 512B writes. For most modern SSDs,
ashift=12 is what you probably want. Oh, and you can’t change this setting without destroying the mirror, so no pressure.
ashift=9(2^9) = 512B sectors
ashift=10(2^10) = 1024B sectors
ashift=11(2^11) = 2048B sectors
ashift=12(2^12) = 4096B sectors
ashift=13(2^13) = 8192B sectors
Here, I’m turning on
relatime (the option that is not in the GUI).
zfs set compression=lz4 intel_mirror zfs set atime=on intel_mirror zfs set relatime=on intel_mirror
Check the status of the mirror and the settings.
zpool status zfs get all intel_mirror | grep 'compression\|atime'
I didn’t cover them here (because everyone’s setup might be different), but below were some extra ZFS-related things I had to take care of.
- Setup email notifications for ZED (ZFS Event Daemon)
- Set an email for the root user (
- Ensure the correct email/user is set in
/etc/zfs/zed.d/zed.rc(you can probably leave
- Setup Postfix to send to a SMTP server (e.g., I’m using an external SMTP server)
- Test email (
echo -e "Subject: Test\n\nThis is a test" | /usr/bin/pvemailforward)
- Set an email for the root user (
- Make sure there is a ZFS scrub cronjob (
- Make sure there is enough RAM for ZFS, as it will use up to 50% of the host’s RAM for ARC. You can change how much is used for ARC, but keep in mind that you’ll see increased RAM usage when you activate ZFS.
Add storage to Proxmox
Add the storage to Proxmox and set the content type to VM images and container root directories.
pvesm add zfspool intel_mirror -pool intel_mirror pvesh set /storage/intel_mirror -content images,rootdir
In the GUI, under
Datacenter-->node_name-->Disks-->ZFS, you should see the mirror.
Datacenter-->Storage, you should see the mirror with the correct content types set.
Shutdown all VMs/CTs that you intend to move to the new storage pool. In the VM
Hardware menu (or CT
Resources menu), select the disk, then click on Disk Action, then Move Storage (you can’t move a VM/CT disk to another storage if you have snapshots).
Then, select the new ZFS mirror.
By default, the source disk is added as an “unused disk” for safety. If you don’t want this, you can select the Delete source box.
For me, an 8GB VM disk took 1 minute to move, and a 55GB VM disk took 8 minutes to move.
I moved three VMs and am going to give them a few days before moving the rest of my VMs/CTs. So far, so good. :man-shrugging:
I will also experiment with alerting scripts for ZFS and possibly a cronjob to send me the output of
zpool status and
smartctl -a /dev/sdX once a month.