Illumos #1051: zfs should handle imbalanced luns

Today zfs tries to allocate blocks evenly across all devices.
This means when devices are imbalanced zfs will use lots of
CPU searching for space on devices which tend to be pretty
full.  It should instead fail quickly on the full LUNs and
move onto devices which have more availability.

Reviewed by: Eric Schrock <[email protected]>
Reviewed by: Matt Ahrens <[email protected]>
Reviewed by: Adam Leventhal <[email protected]>
Reviewed by: Albert Lee <[email protected]>
Reviewed by: Gordon Ross <[email protected]>
Approved by: Garrett D'Amore <[email protected]>

References to Illumos issue and patch:
- https://www.illumos.org/issues/510
- https://github.com/illumos/illumos-gate/commit/5ead3ed965

Signed-off-by: Brian Behlendorf <[email protected]>
Issue #340

1 files changed, 7 insertions, 0 deletions

diff --git a/module/zfs/spa_misc.c b/module/zfs/spa_misc.c
index 487a76d71..e4e0c35f0 100644
--- a/module/zfs/spa_misc.c
+++ b/module/zfs/spa_misc.c
@@ -20,6 +20,7 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 #include <sys/zfs_context.h>
@@ -1680,6 +1681,12 @@ spa_scan_get_stats(spa_t *spa, pool_scan_stat_t *ps)
 	return (0);
 }
 
+boolean_t
+spa_debug_enabled(spa_t *spa)
+{
+	return (spa->spa_debug);
+}
+
 #if defined(_KERNEL) && defined(HAVE_SPL)
 /* Namespace manipulation */
 EXPORT_SYMBOL(spa_lookup);