Rob Norris cbb9ef0a4c ddt: tuneable to override copies= on dedup metadata objects
All objects stored in the MOS get copies=3. For a large dedup table,
this requires significant extra IO and disk space, when its not really
necessary - the dedup table itself isn't needed to read or write data,
only to keep data usage down. Losing the dedup table does not render the
pool unusable, it just messes up the accounting somewhat.

This adds a dmu_ddt_copies tuneable. When set to 0, the existing
behaviour is used. When set higher, dedup table blocks (ZAP and log)
will have this many copies rather than the usual 3, while indirect
blocks will have one more again.

This is a tuneable for now mostly for testing. Losing a dedup table can
cause blocks to be leaked, and we currently have no facilities to repair
that.

Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
Sponsored-by: Klara, Inc.
Sponsored-by: iXsystems, Inc.
Closes #15895
2024-08-16 12:03:27 -07:00
2022-12-22 11:34:28 -08:00
2020-06-09 21:24:09 -07:00
2018-05-29 16:00:33 -07:00
2024-07-16 16:27:54 -07:00
2020-08-26 21:44:41 -07:00
2018-05-29 16:00:33 -07:00
2021-04-02 16:33:40 -07:00
2020-03-16 10:46:03 -07:00

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OpenZFS is an advanced file system and volume manager which was originally developed for Solaris and is now maintained by the OpenZFS community. This repository contains the code for running OpenZFS on Linux and FreeBSD.

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Official Resources

Installation

Full documentation for installing OpenZFS on your favorite operating system can be found at the Getting Started Page.

Contribute & Develop

We have a separate document with contribution guidelines.

We have a Code of Conduct.

Release

OpenZFS is released under a CDDL license. For more details see the NOTICE, LICENSE and COPYRIGHT files; UCRL-CODE-235197

Supported Kernels

  • The META file contains the officially recognized supported Linux kernel versions.
  • Supported FreeBSD versions are any supported branches and releases starting from 13.0-RELEASE.
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