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Alexander Motin 600a02b884
Improve log spacemap load time
Previous flushing algorithm limited only total number of log blocks to
the minimum of 256K and 4x number of metaslabs in the pool.  As result,
system with 1500 disks with 1000 metaslabs each, touching several new
metaslabs each TXG could grow spacemap log to huge size without much
benefits.  We've observed one of such systems importing pool for about
45 minutes.

This patch improves the situation from five sides:
 - By limiting maximum period for each metaslab to be flushed to 1000
TXGs, that effectively limits maximum number of per-TXG spacemap logs
to load to the same number.
 - By making flushing more smooth via accounting number of metaslabs
that were touched after the last flush and actually need another flush,
not just ms_unflushed_txg bump.
 - By applying zfs_unflushed_log_block_pct to the number of metaslabs
that were touched after the last flush, not all metaslabs in the pool.
 - By aggressively prefetching per-TXG spacemap logs up to 16 TXGs in
advance, making log spacemap load process for wide HDD pool CPU-bound,
accelerating it by many times.
 - By reducing zfs_unflushed_log_block_max from 256K to 128K, reducing
single-threaded by nature log processing time from ~10 to ~5 minutes.

As further optimization we could skip bumping ms_unflushed_txg for
metaslabs not touched since the last flush, but that would be an
incompatible change, requiring new pool feature.

Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored-By: iXsystems, Inc.
Closes #12789
2022-04-26 10:44:21 -07:00
.github CI: Log test name to /dev/kmsg in ZTS 2022-03-24 08:01:26 -06:00
cmd man: zfs-send.8: fix -X synopses and description 2022-04-25 12:46:22 -07:00
config Linux 5.18 compat: kobj_type.default_attrs replaced with default_groups 2022-04-22 14:27:10 -07:00
contrib contrib: dracut: remove getargbool polyfill 2022-04-20 16:45:54 -07:00
etc linux: module: weld all but spl.ko into zfs.ko 2022-04-20 13:28:24 -07:00
include Improve log spacemap load time 2022-04-26 10:44:21 -07:00
lib Improve zpool status output, list all affected datasets 2022-04-25 17:25:42 -07:00
man Improve log spacemap load time 2022-04-26 10:44:21 -07:00
module Improve log spacemap load time 2022-04-26 10:44:21 -07:00
rpm linux: module: weld all but spl.ko into zfs.ko 2022-04-20 13:28:24 -07:00
scripts scripts: zfs.sh: explicitly unload all modules via rmmod 2022-04-21 16:33:12 -07:00
tests Improve zpool status output, list all affected datasets 2022-04-25 17:25:42 -07:00
udev Udev rules: remove zvol compat symlinks (without the leading zvol/) 2021-07-06 13:41:17 -07:00
.editorconfig Add an .editorconfig; document git whitespace settings 2020-01-27 13:32:52 -08:00
.gitignore Add FreeBSD support to OpenZFS 2020-04-14 11:36:28 -07:00
.gitmodules .gitmodules: link to openzfs github repository 2021-04-12 09:37:23 -07:00
AUTHORS Add zstd support to zfs 2020-08-20 10:30:06 -07:00
autogen.sh Cause autogen.sh to fail if autoreconf fails 2018-07-06 09:27:37 -07:00
CODE_OF_CONDUCT.md Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
configure.ac linux: module: weld all but spl.ko into zfs.ko 2022-04-20 13:28:24 -07:00
copy-builtin copy-builtin: posix conformance 2021-05-08 08:58:26 -07:00
COPYRIGHT Fix typos 2020-06-09 21:24:09 -07:00
LICENSE Update build system and packaging 2018-05-29 16:00:33 -07:00
Makefile.am linux: module: weld all but spl.ko into zfs.ko 2022-04-20 13:28:24 -07:00
META Linux 5.17 compat: META 2022-03-23 08:52:30 -07:00
NEWS Fix NEWS file 2020-08-26 21:44:41 -07:00
NOTICE Update build system and packaging 2018-05-29 16:00:33 -07:00
README.md README: Update OpenZFS website url 2022-01-06 16:25:01 -08:00
RELEASES.md Add RELEASES.md file 2021-04-02 16:33:40 -07:00
TEST Remove CI builder customization from TEST 2020-03-16 10:46:03 -07:00
zfs.release.in Move zfs.release generation to configure step 2012-07-12 12:22:51 -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 12.2-RELEASE.