22c22
< .\" $FreeBSD: head/cddl/contrib/opensolaris/cmd/zpool/zpool-features.5 239749 2012-08-27 19:52:55Z mm $
---
> .\" $FreeBSD: head/cddl/contrib/opensolaris/cmd/zpool/zpool-features.5 239774 2012-08-28 12:25:37Z mm $
24c24
< .Dd Aug 27, 2012
---
> .Dd Aug 28, 2012
164a165,187
> .It Sy empty_bpobj
> .Bl -column "READ\-ONLY COMPATIBLE" "com.delphix:empty_bpobj"
> .It GUID Ta com.delphix:empty_bpobj
> .It READ\-ONLY COMPATIBLE Ta yes
> .It DEPENDENCIES Ta none
> .El
> .Pp
> This feature increases the performance of creating and using a large number
> of snapshots of a single filesystem or volume, and also reduces the disk
> space required.
> .Pp
> When there are many snapshots, each snapshot uses many Block Pointer Objects
> .Pq bpobj's
> to track blocks associated with that snapshot.
> However, in common use cases, most of these bpobj's are empty.
> This feature allows us to create each bpobj on-demand, thus eliminating the
> empty bpobjs.
> .Pp
> This feature is
> .Sy active
> while there are any filesystems, volumes, or snapshots which were created
> after enabling this feature.
> .El