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Matthew Ahrens
7261fc2e81
For each WRITE record in the stream, `zfs receive` creates a DMU transaction (`dmu_tx_create()`) and writes this block's data into the object. If per-block overheads (as opposed to per-byte overheads) dominate performance (as is often the case with small recordsize), the per-dmu-transaction overheads can be significant. For example, in some workloads the `receieve_writer` thread is 100% on CPU, and more than half of its CPU time is in these per-tx routines (e.g. dmu_tx_hold_write, dmu_tx_assign, dmu_tx_commit). To improve performance of `zfs receive`, this commit batches WRITE records which are to nearby offsets of the same object, and uses one DMU transaction to write them all. By default the batch size is 1MB, which for recordsize=8K reduces the number of DMU transactions by 128x for full send streams (incrementals will depend on how "clumpy" the changed blocks are). This commit improves the performance of `dd if=stream | zfs recv` from 78,800 blocks/sec to 98,100 blocks/sec (25% improvement). Reviewed-by: Paul Dagnelie <pcd@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Matthew Ahrens <mahrens@delphix.com> Closes #10099
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.
Official Resources
- Wiki - for using and developing this repo
- ZoL Site - Linux release info & links
- Mailing lists
- OpenZFS site - for conference videos and info on other platforms (illumos, OSX, Windows, etc)
Installation
Full documentation for installing OpenZFS on your favorite Linux distribution can be found at the ZoL Site.
FreeBSD support is a work in progress. See the PR.
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
METAfile contains the officially recognized supported Linux kernel versions.