Slim Zil; Introduction; Snapshot Deletion; Snapshot Deletion Deferred Update - Oracle Sun ZFS Service Manual

Slim ZIL

Slim ZIL

Introduction

This deferred update changes the layout of ZFS intent log blocks to improve synchronous write
performance. These improvements rely on a ZFS pool upgrade provided by this update. Before
this update has been applied, log records will continue to be written in the old format and
performance may be reduced.
Applying this update is equivalent to upgrading the on-disk ZFS pool to version 23.

Snapshot Deletion

Snapshot Deletion Deferred Update

This deferred update increases snapshot deletion parallelism and reduces the size of transaction
groups associated with snapshot deletion to improve systemic responsiveness. These
improvements rely on a ZFS pool upgrade provided by this update. Before this update has been
applied, new snapshot data will be stored in the old format and deleted using the old algorithm.
Note that any snapshots created before this update is applied will also be deleted using the old
algorithm.
Applying this update is equivalent to upgrading the on-disk ZFS pool version 26.

Recursive Snapshots

Recursive Snapshots Deferred Update

This deferred update allows recursive snapshots to be taken without suspending the ZFS intent
log, which greatly improves snapshot creation performance especially on heavily loaded
controllers. These improvements rely on a ZFS pool upgrade provided by this update. Before
this update has been applied, the system will be able to create snapshots but will do so using the
old, much slower, algorithm.
Applying this update is equivalent to upgrading the on-disk ZFS pool to version 27.
128 Sun ZFS Storage 7x20 Appliance Customer Service Manual • December 2011 E26399–02