From 6c0f78f8a35122e63c9c92475678174d9575afdf Mon Sep 17 00:00:00 2001 From: Richard Laager Date: Sun, 14 Apr 2019 21:30:13 -0500 Subject: [PATCH] Clarify GRUB's lack of support for sha512, skein, edonr zfs.8 correctly said that GRUB did not support them, but zpool-features.5 said that "Booting off pools...is supported." Now, zpool-features.5 discusses GRUB specifically and indicates its lack of support for these features. Also, I have clarified the wording in both places to indicate that the pool feature cannot be used. It's not a filesystem dataset thing, but pool-wide. I described this as "cannot be used". I think technically the feature can be enabled, just not active. However, the effect is essentially the same: you cannot enable those checksum algorithms on any dataset in the pool, so you might as well not enable the feature (which is just pointing a loaded gun at your foot). In the past, an argument could be made that having all the features enabled was useful for simplicity, as long as you didn't activate the GRUB-incompatible features, but that's getting less and less realistic over time. A user can still do that, but we should not encourage that. Reviewed-by: George Melikov Reviewed-by: Brian Behlendorf Signed-off-by: Richard Laager Closes #8626 Closes #8446 --- man/man5/zpool-features.5 | 9 ++++++--- man/man8/zfs.8 | 6 +++--- 2 files changed, 9 insertions(+), 6 deletions(-) diff --git a/man/man5/zpool-features.5 b/man/man5/zpool-features.5 index a5cf7a9ed..2ab74f19b 100644 --- a/man/man5/zpool-features.5 +++ b/man/man5/zpool-features.5 @@ -598,7 +598,8 @@ can turn on the \fBsha512\fR checksum on any dataset using and will return to being \fBenabled\fR once all filesystems that have ever had their checksum set to \fBsha512\fR are destroyed. -Booting off of pools utilizing SHA-512/256 is supported. +The \fBsha512\fR feature is not supported by GRUB and must not be used on +the pool if GRUB needs to access the pool (e.g. for /boot). .RE @@ -632,7 +633,8 @@ can turn on the \fBskein\fR checksum on any dataset using and will return to being \fBenabled\fR once all filesystems that have ever had their checksum set to \fBskein\fR are destroyed. -Booting off of pools using \fBskein\fR is supported. +The \fBskein\fR feature is not supported by GRUB and must not be used on +the pool if GRUB needs to access the pool (e.g. for /boot). .RE @@ -672,7 +674,8 @@ can turn on the \fBedonr\fR checksum on any dataset using the and will return to being \fBenabled\fR once all filesystems that have ever had their checksum set to \fBedonr\fR are destroyed. -Booting off of pools using \fBedonr\fR is supported. +The \fBedonr\fR feature is not supported by GRUB and must not be used on +the pool if GRUB needs to access the pool (e.g. for /boot). .RE diff --git a/man/man8/zfs.8 b/man/man8/zfs.8 index d475df650..eaa98212f 100644 --- a/man/man8/zfs.8 +++ b/man/man8/zfs.8 @@ -1191,9 +1191,9 @@ The and .Sy edonr checksum algorithms require enabling the appropriate features on the pool. -These algorithms are not supported by GRUB and should not be set on the -.Sy bootfs -filesystem when using GRUB to boot the system. +These pool features are not supported by GRUB and must not be used on the +pool if GRUB needs to access the pool (e.g. for /boot). +.Pp Please see .Xr zpool-features 5 for more information on these algorithms. -- 2.40.0