mirror of
https://github.com/openzfs/zfs.git
synced 2025-08-16 22:47:35 +00:00
60f714e6e2
Based on previous commit this implements `zfs rewrite -P` flag, making ZFS to keep blocks logical birth times while rewriting files. It should exclude the rewritten blocks from incremental sends, snapshot diffs, etc. Snapshots space usage same time will reflect the additional space usage from newly allocated blocks. Since this begins to use new "rewrite" flag in the block pointers, this commit introduces a new read-compatible per-dataset feature physical_rewrite. It must be enabled for the command to not fail, it is activated on first use and deactivated on deletion of the last affected dataset. Reviewed-by: Rob Norris <robn@despairlabs.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com> Closes #17565
91 lines
2.8 KiB
Groff
91 lines
2.8 KiB
Groff
.\" SPDX-License-Identifier: CDDL-1.0
|
|
.\"
|
|
.\" CDDL HEADER START
|
|
.\"
|
|
.\" The contents of this file are subject to the terms of the
|
|
.\" Common Development and Distribution License (the "License").
|
|
.\" You may not use this file except in compliance with the License.
|
|
.\"
|
|
.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
|
|
.\" or https://opensource.org/licenses/CDDL-1.0.
|
|
.\" See the License for the specific language governing permissions
|
|
.\" and limitations under the License.
|
|
.\"
|
|
.\" When distributing Covered Code, include this CDDL HEADER in each
|
|
.\" file and include the License file at usr/src/OPENSOLARIS.LICENSE.
|
|
.\" If applicable, add the following below this CDDL HEADER, with the
|
|
.\" fields enclosed by brackets "[]" replaced with your own identifying
|
|
.\" information: Portions Copyright [yyyy] [name of copyright owner]
|
|
.\"
|
|
.\" CDDL HEADER END
|
|
.\"
|
|
.\" Copyright (c) 2025 iXsystems, Inc.
|
|
.\"
|
|
.Dd May 6, 2025
|
|
.Dt ZFS-REWRITE 8
|
|
.Os
|
|
.
|
|
.Sh NAME
|
|
.Nm zfs-rewrite
|
|
.Nd rewrite specified files without modification
|
|
.Sh SYNOPSIS
|
|
.Nm zfs
|
|
.Cm rewrite
|
|
.Oo Fl Prvx Ns Oc
|
|
.Op Fl l Ar length
|
|
.Op Fl o Ar offset
|
|
.Ar file Ns | Ns Ar directory Ns …
|
|
.
|
|
.Sh DESCRIPTION
|
|
Rewrite blocks of specified
|
|
.Ar file
|
|
as is without modification at a new location and possibly with new
|
|
properties, such as checksum, compression, dedup, copies, etc,
|
|
as if they were atomically read and written back.
|
|
.Bl -tag -width "-r"
|
|
.It Fl P
|
|
Perform physical rewrite, preserving logical birth time of blocks.
|
|
By default, rewrite updates logical birth times, making blocks appear
|
|
as modified in snapshots and incremental send streams.
|
|
Physical rewrite preserves logical birth times, avoiding unnecessary
|
|
inclusion in incremental streams.
|
|
Physical rewrite requires the
|
|
.Sy physical_rewrite
|
|
feature to be enabled on the pool.
|
|
.It Fl l Ar length
|
|
Rewrite at most this number of bytes.
|
|
.It Fl o Ar offset
|
|
Start at this offset in bytes.
|
|
.It Fl r
|
|
Recurse into directories.
|
|
.It Fl v
|
|
Print names of all successfully rewritten files.
|
|
.It Fl x
|
|
Don't cross file system mount points when recursing.
|
|
.El
|
|
.Sh NOTES
|
|
Rewrite of cloned blocks and blocks that are part of any snapshots,
|
|
same as some property changes may increase pool space usage.
|
|
Holes that were never written or were previously zero-compressed are
|
|
not rewritten and will remain holes even if compression is disabled.
|
|
.Pp
|
|
If a
|
|
.Fl l
|
|
or
|
|
.Fl o
|
|
value request a rewrite to regions past the end of the file, then those
|
|
regions are silently ignored, and no error is reported.
|
|
.Pp
|
|
By default, rewritten blocks update their logical birth time,
|
|
meaning they will be included in incremental
|
|
.Nm zfs Cm send
|
|
streams as modified data.
|
|
When the
|
|
.Fl P
|
|
flag is used, rewritten blocks preserve their logical birth time, since
|
|
there are no user data changes.
|
|
.
|
|
.Sh SEE ALSO
|
|
.Xr zfsprops 7 ,
|
|
.Xr zpool-features 7
|