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Add BRT support to zpool prefetch command#17890

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behlendorf merged 1 commit into
openzfs:masterfrom
amotin:prefetch
Nov 11, 2025
Merged

Add BRT support to zpool prefetch command#17890
behlendorf merged 1 commit into
openzfs:masterfrom
amotin:prefetch

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@amotin amotin commented Nov 3, 2025

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).

How Has This Been Tested?

Manually from command line, prefetching the BRT and observing dramatically better delete performance for large cloned files after.

Types of changes

  • Bug fix (non-breaking change which fixes an issue)
  • New feature (non-breaking change which adds functionality)
  • Performance enhancement (non-breaking change which improves efficiency)
  • Code cleanup (non-breaking change which makes code smaller or more readable)
  • Quality assurance (non-breaking change which makes the code more robust against bugs)
  • Breaking change (fix or feature that would cause existing functionality to change)
  • Library ABI change (libzfs, libzfs_core, libnvpair, libuutil and libzfsbootenv)
  • Documentation (a change to man pages or other documentation)

Checklist:
@amotin amotin force-pushed the prefetch branch 2 times, most recently from c60d233 to b6603fd Compare November 4, 2025 16:36
@amotin amotin added the Status: Code Review Needed Ready for review and testing label Nov 4, 2025
behlendorf
behlendorf approved these changes Nov 7, 2025
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Looks good to me, nice and straight forward.
Comment thread cmd/zpool/zpool_main.c Outdated
@amotin
Add BRT support to zpool prefetch command
560b42f 
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).

Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
@amotin amotin added Status: Accepted Ready to integrate (reviewed, tested) and removed Status: Code Review Needed Ready for review and testing labels Nov 11, 2025
@behlendorf behlendorf merged commit b4f073b into openzfs:master Nov 11, 2025
21 of 25 checks passed
@amotin amotin deleted the prefetch branch November 11, 2025 13:59
behlendorf pushed a commit to behlendorf/zfs that referenced this pull request Nov 12, 2025
@amotin @behlendorf
Add BRT support to zpool prefetch command
41878d5 
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 openzfs#17890
kithrup pushed a commit to KlaraSystems/zfs that referenced this pull request Dec 17, 2025
@amotin @kithrup
Add BRT support to zpool prefetch command
0c01aa7 
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 openzfs#17890
lundman pushed a commit to openzfsonosx/openzfs-fork that referenced this pull request Jan 30, 2026
@amotin @lundman
Add BRT support to zpool prefetch command
8badff9 
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 openzfs#17890
lundman pushed a commit to openzfsonwindows/openzfs that referenced this pull request Feb 23, 2026
@amotin @lundman
Add BRT support to zpool prefetch command
1ee7ac2 
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 openzfs#17890
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Status: Accepted Ready to integrate (reviewed, tested)

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@amotin @behlendorf