diff options
Diffstat (limited to 'cddl/contrib/opensolaris/cmd/zfs/zfs.8')
-rw-r--r-- | cddl/contrib/opensolaris/cmd/zfs/zfs.8 | 51 |
1 files changed, 49 insertions, 2 deletions
diff --git a/cddl/contrib/opensolaris/cmd/zfs/zfs.8 b/cddl/contrib/opensolaris/cmd/zfs/zfs.8 index b9760c4..d0f21d3 100644 --- a/cddl/contrib/opensolaris/cmd/zfs/zfs.8 +++ b/cddl/contrib/opensolaris/cmd/zfs/zfs.8 @@ -18,7 +18,7 @@ .\" information: Portions Copyright [yyyy] [name of copyright owner] .\" .\" Copyright (c) 2010, Sun Microsystems, Inc. All Rights Reserved. -.\" Copyright (c) 2013 by Delphix. All rights reserved. +.\" Copyright (c) 2014 by Delphix. All rights reserved. .\" Copyright (c) 2011, Pawel Jakub Dawidek <pjd@FreeBSD.org> .\" Copyright (c) 2012, Glen Barber <gjb@FreeBSD.org> .\" Copyright (c) 2012, Bryan Drewery <bdrewery@FreeBSD.org> @@ -30,7 +30,7 @@ .\" .\" $FreeBSD$ .\" -.Dd April 23, 2014 +.Dd May 27, 2014 .Dt ZFS 8 .Os .Sh NAME @@ -1193,6 +1193,53 @@ affects only files created afterward; existing files are unaffected. .Pp This property can also be referred to by its shortened column name, .Sy recsize . +.It Sy redundant_metadata Ns = Ns Cm all | most +Controls what types of metadata are stored redundantly. +ZFS stores an extra copy of metadata, so that if a single block is corrupted, +the amount of user data lost is limited. +This extra copy is in addition to any redundancy provided at the pool level +.Pq e.g. by mirroring or RAID-Z , +and is in addition to an extra copy specified by the +.Sy copies +property +.Pq up to a total of 3 copies . +For example if the pool is mirrored, +.Cm copies Ns = Ns Ar 2 , +and +.Cm redundant_metadata Ns = Ns Ar most , +then ZFS +stores 6 copies of most metadata, and 4 copies of data and some +metadata. +.Pp +When set to +.Cm all , +ZFS stores an extra copy of all metadata. +If a +single on-disk block is corrupt, at worst a single block of user data +.Po which is +.Cm recordsize +bytes long +can be lost. +.Pc +.Pp +When set to +.Cm most , +ZFS stores an extra copy of most types of +metadata. +This can improve performance of random writes, because less +metadata must be written. +In practice, at worst about 100 blocks +.Po of +.Cm recordsize +bytes each +.Pc +of user data can be lost if a single +on-disk block is corrupt. +The exact behavior of which metadata blocks +are stored redundantly may change in future releases. +.Pp +The default value is +.Cm all . .It Sy refquota Ns = Ns Ar size | Cm none Limits the amount of space a dataset can consume. This property enforces a hard limit on the amount of space used. This hard limit does not include space used |