From 4339b4eb2f1a32290b0eb7f4332b24e9f72dd55f Mon Sep 17 00:00:00 2001 From: shelvacu <1731537+shelvacu@users.noreply.github.com> Date: Mon, 20 Apr 2026 10:05:31 -0700 Subject: [PATCH] zpool-labelclear.8: Warn that it's destructive If I could go back in time, I would beg Sun engineers to pick a different name. For those of us who have not read the ZFS On-Disk Specification pdf, it is not at all obvious that clearing a "label" is such a bad thing. But changing the name would be a breaking change, so at least for now we can update the documentation. Reviewed-by: Brian Behlendorf Reviewed-by: Tony Hutter Signed-off-by: Shelvacu Closes #18347 --- man/man8/zpool-labelclear.8 | 9 +++++++++ man/man8/zpool.8 | 4 +++- 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/man/man8/zpool-labelclear.8 b/man/man8/zpool-labelclear.8 index b807acaaede..65b2f6c4fd3 100644 --- a/man/man8/zpool-labelclear.8 +++ b/man/man8/zpool-labelclear.8 @@ -50,6 +50,15 @@ is a cache device, it also removes the L2ARC header The .Ar device must not be part of an active pool configuration. +.Pp +This overwrites pool metadata, making all data on the +.Ar device +inaccessible without specialized recovery tools. +Unlike +.Nm zpool Cm destroy , +this cannot be undone by ZFS tooling. +Only use this when you don't care about the data on the +.Ar device . .Bl -tag -width Ds .It Fl f Treat exported or foreign devices as inactive. diff --git a/man/man8/zpool.8 b/man/man8/zpool.8 index 3bfef780b29..4b07f96bbcb 100644 --- a/man/man8/zpool.8 +++ b/man/man8/zpool.8 @@ -108,7 +108,9 @@ specified. Destroys the given pool, freeing up any devices for other use. .It Xr zpool-labelclear 8 Removes ZFS label information from the specified -.Ar device . +.Ar device , +making all data inaccessible without specialized recovery tools. +Cannot be undone with ZFS tooling. .El . .Ss Virtual Devices