mirror_zfs/lib
Rob Norris cd69ba3d49 ddt: dedup log
Adds a log/journal to dedup. At the end of txg, instead of writing the
entry directly to the ZAP, instead its adding to an in-memory tree and
appended to an on-disk object. The on-disk object is only read at
import, to reload the in-memory tree.

Lookups first go the the log tree before going to the ZAP, so
recently-used entries will remain close by in memory. This vastly
reduces overhead from dedup IO, as it will not have to do so many
read/update/write cycles on ZAP leaf nodes.

A flushing facility is added at end of txg, to push logged entries out
to the ZAP. There's actually two separate "logs" (in-memory tree and
on-disk object), one active (recieving updated entries) and one flushing
(writing out to disk). These are swapped (ie flushing begins) based on
memory used by the in-memory log trees and time since we last flushed
something.

The flushing facility monitors the amount of entries coming in and being
flushed out, and calibrates itself to try to flush enough each txg to
keep up with the ingest rate without competing too much with other IO.
Multiple tuneables are provided to control the flushing facility.

All the histograms and stats are update to accomodate the log as a
separate entry store. zdb gains knowledge of how to count them and dump
them. Documentation included!

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 12:03:35 -07:00
..
libavl cppcheck: explicitly exclude kernel code from userspace checks 2022-05-10 10:20:55 -07:00
libefi Replace P2ALIGN with P2ALIGN_TYPED and delete P2ALIGN. 2024-05-10 08:47:21 -07:00
libicp icp: remove skein module 2024-05-31 15:13:39 -07:00
libnvpair libspl: lift backtrace into a separate file 2024-05-14 09:48:45 -07:00
libshare Add support for multiple lines to the sharenfs property for FreeBSD (#16338) 2024-07-23 16:38:19 -07:00
libspl JSON output support for zpool status 2024-08-06 12:47:10 -07:00
libtpool tpool_dispatch: fail if it cannot start at least 1 worker. 2024-05-14 09:35:48 -07:00
libunicode cppcheck: explicitly exclude kernel code from userspace checks 2022-05-10 10:20:55 -07:00
libuutil JSON output support for zpool status 2024-08-06 12:47:10 -07:00
libzdb Provide macros for setting and getting blkptr birth times 2024-03-25 15:01:54 -07:00
libzfs ddt: add FDT feature and support for legacy and new on-disk formats 2024-08-16 11:58:59 -07:00
libzfs_core JSON output support for zpool status 2024-08-06 12:47:10 -07:00
libzfsbootenv nvpair: Constify string functions 2023-03-14 15:25:50 -07:00
libzpool ddt: dedup log 2024-08-16 12:03:35 -07:00
libzstd cppcheck: explicitly exclude kernel code from userspace checks 2022-05-10 10:20:55 -07:00
libzutil libzfs: use zfs_strerror() in place of strerror() 2024-01-29 09:54:57 -08:00
Makefile.am libzdb: Initial breakout of libzdb 2024-02-05 10:00:41 -08:00