Hi, can I temporarily disconnect a pool made of a mirrored VDEV to protect my data while fiddling around with Truenas?
Should I zpool export? I upgraded to the latest ZFS version.
When I’m done setting up apps etc. I want to import them again.
EDIT: And keep all the datasets, ACL and share settings intact preferably.
You can export a pool with the GUI.
Do you mean the latest TrueNAS version?
Yes latest Truenas version. I started from EE and went to Fangtooth. But I got a few warnings that updating ZFS on all pools has the possible implication of not being compatible with older version. Specifically about flags. Don’t really now what that is.
I want to take 3 HDD down. 2 pools. 2 VDEVs. One 2 HDD mirror pool and one 1 HDD stripe pool.
They contain valuable data.
The datasets on the mirrored VDEV have a lot of shares and was a lot of work to set up. I want to keep those settings and ACLs intact.
Is this possible? Even after altering the rest of my system?
To give an idea. I have 9 pools. But 7 of them aren’t that important.
EDIT: I was a Synology user for years and wanted to expand my storage and capability of running VM’s and containerized apps. But their hardware is so old, though their DSM (OS) is very user friendly and robust.
Now I want to set up network bridges, VMs and a lot of apps. Have a powerful machine. But I almost locked myself out of Truenas while fiddling around today. So to avoid dataloss, I want to keep it safe while disconnected.
Yes, you can safely export a pool from the GUI. Just make sure to first export your config (with the secret seed) and export all encryption keys.
When you export a pool, uncheck the option to “Delete configuration of shares that used this pool”.
I shouldn’t have to tell you to keep “Destroy data on this pool” unchecked.
No. Not destroy data obviously.
I have imported a ZFS pool from Proxmox before. But it was a “dirty” process. And it was only a one disk VDEV/pool. Couldn’t name it the same.
But never imported a pool/VDEV that I exported from Truenas before. Hence the question.
Will my share and ACLs be still good?
ACLs are stored on the filesystems. When you import a pool with existing datasets, each dataset’s filesystem properties exist as they did before the pool was exported.
The shares shouldn’t be automatically deleted if you keep that “Delete shares” option unchecked during export.
ZFS uses feature flags to indicate whether certain ZFS features are supported by a pool. You can only import a pool on a system running a version of ZFS that understands all of the feature flags on that pool.
iX Systems writes new features and sometimes these are gated by feature flags. TrueNAS tends to lean-in and support them sometimes before they’re “upstreamed” into OpenZFS. So in some cases your TrueNAS pool might only be importable on TrueNAS for awhile. This may or may not be what you want.
The reason for feature flags is that they indicate a change to the on-disk format of ZFS. This is why they must be supported on a system to import a pool. Otherwise data corruption or other undefined behavior could result.
You may manually enable select feature flags from the CLI on any system that supports the feature flag you wish to enable. This is typically not recommended on TrueNAS because the GUI is the only supported way to upgrade a pool.
It’s worth noting that you can look into ZFS checkpoints for further reading on how to “safe” a pool for major changes in a reversible manner. (Checkpoints cannot save you from everything, however.)
