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mirror_zfs/man/man8/zpool-prefetch.8

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SPDX: license tags: CDDL-1.0 Sponsored-by: https://despairlabs.com/sponsor/ Signed-off-by: Rob Norris <robn@despairlabs.com> Reviewed-by: Tony Hutter <hutter2@llnl.gov> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
2025-01-04 03:04:27 +03:00
.\" SPDX-License-Identifier: CDDL-1.0
ddt: add support for prefetching tables into the ARC This change adds a new `zpool prefetch -t ddt $pool` command which causes a pool's DDT to be loaded into the ARC. The primary goal is to remove the need to "warm" a pool's cache before deduplication stops slowing write performance. It may also provide a way to reload portions of a DDT if they have been flushed due to inactivity. Sponsored-by: iXsystems, Inc. Sponsored-by: Catalogics, Inc. Sponsored-by: Klara, Inc. Reviewed-by: Alexander Motin <mav@FreeBSD.org> Reviewed-by: Tony Hutter <hutter2@llnl.gov> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Allan Jude <allan@klarasystems.com> Signed-off-by: Will Andrews <will.andrews@klarasystems.com> Signed-off-by: Fred Weigel <fred.weigel@klarasystems.com> Signed-off-by: Rob Norris <rob.norris@klarasystems.com> Signed-off-by: Don Brady <don.brady@klarasystems.com> Co-authored-by: Will Andrews <will.andrews@klarasystems.com> Co-authored-by: Don Brady <don.brady@klarasystems.com> Closes #15890
2024-07-26 19:16:18 +03:00
.\"
.\" 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.
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.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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.\"
.\"
.\" Copyright (c) 2023, Klara Inc.
.\"
.Dd February 14, 2024
.Dt ZPOOL-PREFETCH 8
.Os
.
.Sh NAME
.Nm zpool-prefetch
Add BRT support to zpool prefetch command Implement BRT (Block Reference Table) prefetch functionality similar to existing DDT prefetch. This allows preloading BRT metadata into ARC to improve performance for block cloning operations and frees of earlier cloned blocks. Make -t parameter optional. When omitted, prefetch all supported metadata types (both DDT and BRT now). Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com> Closes #17890
2025-11-11 03:16:22 +03:00
.Nd Prefetches pool metadata into ARC
ddt: add support for prefetching tables into the ARC This change adds a new `zpool prefetch -t ddt $pool` command which causes a pool's DDT to be loaded into the ARC. The primary goal is to remove the need to "warm" a pool's cache before deduplication stops slowing write performance. It may also provide a way to reload portions of a DDT if they have been flushed due to inactivity. Sponsored-by: iXsystems, Inc. Sponsored-by: Catalogics, Inc. Sponsored-by: Klara, Inc. Reviewed-by: Alexander Motin <mav@FreeBSD.org> Reviewed-by: Tony Hutter <hutter2@llnl.gov> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Allan Jude <allan@klarasystems.com> Signed-off-by: Will Andrews <will.andrews@klarasystems.com> Signed-off-by: Fred Weigel <fred.weigel@klarasystems.com> Signed-off-by: Rob Norris <rob.norris@klarasystems.com> Signed-off-by: Don Brady <don.brady@klarasystems.com> Co-authored-by: Will Andrews <will.andrews@klarasystems.com> Co-authored-by: Don Brady <don.brady@klarasystems.com> Closes #15890
2024-07-26 19:16:18 +03:00
.Sh SYNOPSIS
.Nm zpool
.Cm prefetch
Add BRT support to zpool prefetch command Implement BRT (Block Reference Table) prefetch functionality similar to existing DDT prefetch. This allows preloading BRT metadata into ARC to improve performance for block cloning operations and frees of earlier cloned blocks. Make -t parameter optional. When omitted, prefetch all supported metadata types (both DDT and BRT now). Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com> Closes #17890
2025-11-11 03:16:22 +03:00
.Op Fl t Ar type
ddt: add support for prefetching tables into the ARC This change adds a new `zpool prefetch -t ddt $pool` command which causes a pool's DDT to be loaded into the ARC. The primary goal is to remove the need to "warm" a pool's cache before deduplication stops slowing write performance. It may also provide a way to reload portions of a DDT if they have been flushed due to inactivity. Sponsored-by: iXsystems, Inc. Sponsored-by: Catalogics, Inc. Sponsored-by: Klara, Inc. Reviewed-by: Alexander Motin <mav@FreeBSD.org> Reviewed-by: Tony Hutter <hutter2@llnl.gov> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Allan Jude <allan@klarasystems.com> Signed-off-by: Will Andrews <will.andrews@klarasystems.com> Signed-off-by: Fred Weigel <fred.weigel@klarasystems.com> Signed-off-by: Rob Norris <rob.norris@klarasystems.com> Signed-off-by: Don Brady <don.brady@klarasystems.com> Co-authored-by: Will Andrews <will.andrews@klarasystems.com> Co-authored-by: Don Brady <don.brady@klarasystems.com> Closes #15890
2024-07-26 19:16:18 +03:00
.Ar pool
.Sh DESCRIPTION
Add BRT support to zpool prefetch command Implement BRT (Block Reference Table) prefetch functionality similar to existing DDT prefetch. This allows preloading BRT metadata into ARC to improve performance for block cloning operations and frees of earlier cloned blocks. Make -t parameter optional. When omitted, prefetch all supported metadata types (both DDT and BRT now). Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com> Closes #17890
2025-11-11 03:16:22 +03:00
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.
ddt: add support for prefetching tables into the ARC This change adds a new `zpool prefetch -t ddt $pool` command which causes a pool's DDT to be loaded into the ARC. The primary goal is to remove the need to "warm" a pool's cache before deduplication stops slowing write performance. It may also provide a way to reload portions of a DDT if they have been flushed due to inactivity. Sponsored-by: iXsystems, Inc. Sponsored-by: Catalogics, Inc. Sponsored-by: Klara, Inc. Reviewed-by: Alexander Motin <mav@FreeBSD.org> Reviewed-by: Tony Hutter <hutter2@llnl.gov> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Allan Jude <allan@klarasystems.com> Signed-off-by: Will Andrews <will.andrews@klarasystems.com> Signed-off-by: Fred Weigel <fred.weigel@klarasystems.com> Signed-off-by: Rob Norris <rob.norris@klarasystems.com> Signed-off-by: Don Brady <don.brady@klarasystems.com> Co-authored-by: Will Andrews <will.andrews@klarasystems.com> Co-authored-by: Don Brady <don.brady@klarasystems.com> Closes #15890
2024-07-26 19:16:18 +03:00
.El
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