svn commit: r301096 - in head/cddl/contrib/opensolaris/cmd: zfs zpool
Allan Jude
allanjude at FreeBSD.org
Wed Jun 1 03:36:32 UTC 2016
Author: allanjude
Date: Wed Jun 1 03:36:31 2016
New Revision: 301096
URL: https://svnweb.freebsd.org/changeset/base/301096
Log:
Update zfs(8) and zpool-features(7) man pages with new hashing algorithms
Sponsored by: ScaleEngine Inc.
Modified:
head/cddl/contrib/opensolaris/cmd/zfs/zfs.8
head/cddl/contrib/opensolaris/cmd/zpool/zpool-features.7
Modified: head/cddl/contrib/opensolaris/cmd/zfs/zfs.8
==============================================================================
--- head/cddl/contrib/opensolaris/cmd/zfs/zfs.8 Wed Jun 1 03:27:33 2016 (r301095)
+++ head/cddl/contrib/opensolaris/cmd/zfs/zfs.8 Wed Jun 1 03:36:31 2016 (r301096)
@@ -31,7 +31,7 @@
.\"
.\" $FreeBSD$
.\"
-.Dd October 24, 2015
+.Dd May 31, 2016
.Dt ZFS 8
.Os
.Sh NAME
@@ -940,7 +940,7 @@ command or unmounted by the
command.
.Pp
This property is not inherited.
-.It Sy checksum Ns = Ns Cm on | off | fletcher2 | fletcher4 | sha256 | noparity
+.It Sy checksum Ns = Ns Cm on | off | fletcher2 | fletcher4 | sha256 | noparity | sha512 | skein
Controls the checksum used to verify data integrity. The default value is
.Cm on ,
which automatically selects an appropriate algorithm (currently,
@@ -957,6 +957,16 @@ not be used by any other dataset.
Disabling checksums is
.Em NOT
a recommended practice.
+The
+.Sy sha512 ,
+and
+.Sy skein
+checksum algorithms require enabling the appropriate features on the pool.
+Please see
+.Xr zpool-features 7
+for more information on these algorithms.
+.Pp
+Changing this property affects only newly-written data.
.It Sy compression Ns = Ns Cm on | off | lzjb | gzip | gzip- Ns Ar N | Cm zle | Cm lz4
Controls the compression algorithm used for this dataset.
Setting compression to
@@ -1036,7 +1046,7 @@ Changing this property only affects newl
property at file system creation time by using the
.Fl o Cm copies= Ns Ar N
option.
-.It Sy dedup Ns = Ns Cm on | off | verify | sha256 Ns Op Cm ,verify
+.It Sy dedup Ns = Ns Cm on | off | verify | sha256 Ns Oo Cm ,verify Oc | Sy sha512 Ns Oo Cm ,verify Oc | Sy skein Ns Oo Cm ,verify Oc
Configures deduplication for a dataset. The default value is
.Cm off .
The default deduplication checksum is
Modified: head/cddl/contrib/opensolaris/cmd/zpool/zpool-features.7
==============================================================================
--- head/cddl/contrib/opensolaris/cmd/zpool/zpool-features.7 Wed Jun 1 03:27:33 2016 (r301095)
+++ head/cddl/contrib/opensolaris/cmd/zpool/zpool-features.7 Wed Jun 1 03:36:31 2016 (r301096)
@@ -23,7 +23,7 @@
.\"
.\" $FreeBSD$
.\"
-.Dd November 10, 2014
+.Dd May 31, 2016
.Dt ZPOOL-FEATURES 7
.Os
.Sh NAME
@@ -454,6 +454,97 @@ Please note that booting from datasets t
supported by the
.Fx
boot loader.
+.It Sy sha512
+.Bl -column "READ\-ONLY COMPATIBLE" "org.illumos:sha512"
+.It GUID Ta org.illumos:sha512
+.It READ\-ONLY COMPATIBLE Ta no
+.It DEPENDENCIES Ta none
+.El
+.Pp
+The
+.Sy sha512
+feature enables the use of the SHA-512/256 truncated hash algorithm
+.Pq FIPS 180-4
+for checksum and dedup.
+The native 64-bit arithmetic of SHA-512 provides an approximate 50%
+performance boost over SHA-256 on 64-bit hardware and is thus a good
+minimum-change replacement candidate for systems where hash performance is
+important, but these systems cannot for whatever reason utilize the faster
+.Sy skein
+algorithms.
+.Pp
+When the
+.Sy sha512
+feature is set to
+.Sy enabled ,
+the administrator can turn on the
+.Sysha512
+checksum on any dataset using the
+.Dl # zfs set checksum=sha512 Ar dataset
+command.
+This feature becomes
+.Sy active
+once a
+.Sy checksum
+property has been set to
+.Sy sha512 ,
+and will return to being
+.Sy enabled
+once all filesystems that have ever had their checksum set to
+.Sy sha512
+are destroyed.
+.Pp
+Booting off of a pools utilizing SHA-512/256 is
+.Em NOT
+yet supported.
+.It Sy skein
+.Bl -column "READ\-ONLY COMPATIBLE" "org.illumos:skein"
+.It GUID Ta org.illumos:skein
+.It READ\-ONLY COMPATIBLE Ta no
+.It DEPENDENCIES Ta none
+.El
+.Pp
+The
+.Sy skein
+feature enables the use of the Skein hash algorithm for checksum and dedup.
+Skein is a high-performance secure hash algorithm that was a finalist in the
+NIST SHA-3 competition.
+It provides a very high security margin and high performance on 64-bit hardware
+.Pq 80% faster than SHA-256 .
+This implementation also utilizes the new salted checksumming functionality in
+ZFS, which means that the checksum is pre-seeded with a secret 256-bit random
+key
+.Pq stored on the pool
+before being fed the data block to be checksummed.
+Thus the produced checksums are unique to a given pool, preventing hash
+collision attacks on systems with dedup.
+.Pp
+When the
+.Sy skein
+feature is set to
+.Sy enabled ,
+the administrator can turn on the
+.Sy skein
+checksum on any dataset using the
+.Dl # zfs set checksum=skein Ar dataset
+command.
+This feature becomes
+.Sy active
+once a
+.Sy checksum
+property has been set to
+.Sy skein ,
+and will return to being
+.Sy enabled
+once all filesystems that have ever had their checksum set to
+.Sy skein
+are destroyed.
+.Pp
+Booting off of pools using
+.Sy skein
+is
+.Em NOT
+supported.
.El
.Sh SEE ALSO
.Xr zpool 8
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