8414 Implemented zpool scrub pause/resume

illumos/illumos-gate@1702cce751c5cb7ead878d0205a6c90b027e3de8
https://github.com/illumos/illumos-gate/commit/1702cce751c5cb7ead878d0205a6c90b027e3de8

https://www.illumos.org/issues/8414
  This issue tracks the port of scrub pause from ZoL: https://github.com/zfsonlinux/zfs/pull/6167
  Currently, there is no way to pause a scrub. Pausing may be useful when
 the pool is busy with other I/O to preserve bandwidth.

  Description

  This patch adds the ability to pause and resume scrubbing.  This is achieved
  by maintaining a persistent on-disk scrub state.  While the state is 'paused'
  we do not scrub any more blocks.  We do however perform regular scan
  housekeeping such as freeing async destroyed and deadlist blocks while paused.

  If you're testing this change, you probably want to include the patch from #6164

  Motivation and Context

  Scrub pausing can be an I/O intensive operation and people have been asking
  for the ability to pause a scrub for a while. This allows one to preserve scrub
  progress while freeing up bandwidth for other I/O.

  How Has This Been Tested?

  Unit testing and zfs-tests.  to the pool.  This patch will also include the
  patch from https://github.com/zfsonlinux/zfs/ pull/6164 In certain cases
  (dsl_scan_sync() is one), we may end up calling

Reviewed by: George Melikov <mail@gmelikov.ru>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Reviewed by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Approved by: Dan McDonald <danmcd@joyent.com>
Author: Alek Pinchuk <apinchuk@datto.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/lib/libzfs/common/libzfs_util.c b/lib/libzfs/common/libzfs_util.c
index b8a16a08d454..6910c1d127d4 100644
--- a/lib/libzfs/common/libzfs_util.c
+++ b/lib/libzfs/common/libzfs_util.c
@@ -24,6 +24,7 @@
  * Copyright (c) 2013, Joyent, Inc. All rights reserved.
  * Copyright (c) 2011, 2015 by Delphix. All rights reserved.
  * Copyright 2016 Igor Kozhukhov <ikozhukhov@gmail.com>
+ * Copyright (c) 2017 Datto Inc.
  */
 
 /*
@@ -219,6 +220,9 @@ libzfs_error_description(libzfs_handle_t *hdl)
 	case EZFS_POSTSPLIT_ONLINE:
 		return (dgettext(TEXT_DOMAIN, "disk was split from this pool "
 		    "into a new one"));
+	case EZFS_SCRUB_PAUSED:
+		return (dgettext(TEXT_DOMAIN, "scrub is paused; "
+		    "use 'zpool scrub' to resume"));
 	case EZFS_SCRUBBING:
 		return (dgettext(TEXT_DOMAIN, "currently scrubbing; "
 		    "use 'zpool scrub -s' to cancel current scrub"));