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Paul Dagnelie dd429b46b7 OpenZFS 8056 - zfs send size estimate is inaccurate for some zvols
Authored by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Reviewed-by: Kash Pande <kash@tripleback.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Ported-by: Giuseppe Di Natale <dinatale2@llnl.gov>

The send size estimate for a zvol can be too low, if the size of the
record headers (dmu_replay_record_t's) is a significant portion of the
size. This is typically the case when the data is highly compressible,
especially with embedded blocks.

The problem is that dmu_adjust_send_estimate_for_indirects() assumes
that blocks are the size of the "recordsize" property (128KB). However,
for zvols, the blocks are the size of the "volblocksize" property (8KB).
Therefore, we estimate that there will be 16x less record headers than
there really will be.

The fix is to check the type of the object set (whether it is a zvol or
not) and pick the appropriate property. In addition, while we are at it,
we also add the size of the BEGIN and END records to the estimate.

OpenZFS-issue: https://www.illumos.org/issues/8056
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/faf09cd
Closes #6205
2017-06-09 09:46:14 -07:00
.github Explain reason for Signed-off-by in CONTRIBUTING 2017-05-31 07:30:07 -07:00
cmd OpenZFS 7578 - Fix/improve some aspects of ZIL writing 2017-06-09 09:15:37 -07:00
config config: allow --with-linux without --with-linux-obj 2017-05-25 10:14:13 -07:00
contrib Fix initramfs hook for merged /usr/lib and /lib 2017-02-27 12:03:23 -08:00
etc zpool iostat/status -c improvements 2017-06-05 10:52:15 -07:00
include OpenZFS 8199 - multi-threaded dmu_object_alloc() 2017-06-09 09:43:26 -07:00
lib Fix import finding spare/l2cache when path changes 2017-06-01 06:38:04 -07:00
man OpenZFS 7578 - Fix/improve some aspects of ZIL writing 2017-06-09 09:15:37 -07:00
module OpenZFS 8056 - zfs send size estimate is inaccurate for some zvols 2017-06-09 09:46:14 -07:00
rpm zpool iostat/status -c improvements 2017-06-05 10:52:15 -07:00
scripts zpool iostat/status -c improvements 2017-06-05 10:52:15 -07:00
tests Skip tests that are slow on 32-bit builders 2017-06-06 19:04:01 -07:00
udev Fix spelling 2017-01-03 11:31:18 -06:00
.gitignore Improve gitignore 2017-05-25 10:14:13 -07:00
.gitmodules Add zimport.sh compatibility test script 2014-02-21 12:10:31 -08:00
AUTHORS Add a missing > to AUTHORS 2014-09-02 14:18:53 -07:00
autogen.sh build: do not call boilerplate ourself 2013-04-02 10:55:20 -07:00
configure.ac zpool iostat/status -c improvements 2017-06-05 10:52:15 -07:00
copy-builtin Allow c99 when building ZFS in the kernel tree 2017-03-27 12:31:15 -07:00
COPYRIGHT Update ZED copyright boilerplate 2015-05-11 15:07:00 -07:00
DISCLAIMER Fix minor typos and update marketing copy. 2013-03-21 12:51:06 -07:00
Makefile.am Prebaked scripts for zpool status/iostat -c 2017-04-21 09:27:04 -07:00
META Tag 0.7.0-rc4 2017-05-05 10:33:40 -07:00
OPENSOLARIS.LICENSE Add CDDL license file 2008-12-01 14:49:34 -08:00
README.markdown Add CONTRIBUTING information and templates 2016-12-09 12:48:12 -07:00
TEST Retire filebench testing 2017-06-01 06:24:28 -07:00
zfs-script-config.sh.in zpool iostat/status -c improvements 2017-06-05 10:52:15 -07:00
zfs.release.in Move zfs.release generation to configure step 2012-07-12 12:22:51 -07:00

ZFS is an advanced file system and volume manager which was originally developed for Solaris and is now maintained by the Illumos community.

ZFS on Linux, which is also known as ZoL, is currently feature complete. It includes fully functional and stable SPA, DMU, ZVOL, and ZPL layers. And it's native!

Official Resources

Installation

Full documentation for installing ZoL on your favorite Linux distribution can be found at our site.

Contribute & Develop

We have a separate document with contribution guidelines.