diff options
Diffstat (limited to 'sys/contrib/openzfs/man/man8/zpool-prefetch.8')
| -rw-r--r-- | sys/contrib/openzfs/man/man8/zpool-prefetch.8 | 27 |
1 files changed, 16 insertions, 11 deletions
diff --git a/sys/contrib/openzfs/man/man8/zpool-prefetch.8 b/sys/contrib/openzfs/man/man8/zpool-prefetch.8 index a36ad52e681e..6f4c3b129040 100644 --- a/sys/contrib/openzfs/man/man8/zpool-prefetch.8 +++ b/sys/contrib/openzfs/man/man8/zpool-prefetch.8 @@ -28,20 +28,25 @@ . .Sh NAME .Nm zpool-prefetch -.Nd Loads specific types of data for the given pool +.Nd Prefetches pool metadata into ARC .Sh SYNOPSIS .Nm zpool .Cm prefetch -.Fl t Ar type +.Op Fl t Ar type .Ar pool .Sh DESCRIPTION -.Bl -tag -width Ds -.It Xo -.Nm zpool -.Cm prefetch -.Fl t Li ddt -.Ar pool -.Xc -Prefetch data of a specific type for the given pool; specifically the DDT, -which will improve write I/O performance when the DDT is resident in the ARC. +Massively prefetch metadata of a specific type for the given pool into the ARC +to reduce latency of some operations later. +If no type is specified, all types are prefetched. +.Pp +The following types are supported: +.Bl -tag -width "brt" +.It Sy brt +Prefetch the BRT (block reference table). +This may improve performance for block cloning operations, +and frees for earlier cloned blocks. +.It Sy ddt +Prefetch the DDT (deduplication table). +This may improve performance of writes when deduplication is enabled, +and frees for earlier deduplicated blocks. .El |