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 _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
