Update the default for zfs_txg_history

It's often useful to have access to txg history for debugging
purposes. This patch changes the default from 0 to 100 TXGs
worth of history preserved.

Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Richard Elling <Richard.Elling@RichardElling.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Alek Pinchuk <apinchuk@datto.com>
Closes #6691

diff --git a/man/man5/zfs-module-parameters.5 b/man/man5/zfs-module-parameters.5
index 6e04b4977d800687118fc9d0bf5085a525fce1d9..19ecde4f462e2ec0a9b6760f7c0c11b7a0897325 100644 (file)
--- a/man/man5/zfs-module-parameters.5
+++ b/man/man5/zfs-module-parameters.5
@@ -12,7 +12,7 @@
 .\" CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your
 .\" own identifying information:
 .\" Portions Copyright [yyyy] [name of copyright owner]
-.TH ZFS-MODULE-PARAMETERS 5 "Nov 16, 2013"
+.TH ZFS-MODULE-PARAMETERS 5 "Sept 28, 2017"
 .SH NAME
 zfs\-module\-parameters \- ZFS module parameters
 .SH DESCRIPTION
@@ -1766,7 +1766,7 @@ Default value: \fB32\fR.
 Historical statistics for the last N txgs will be available in
 \fB/proc/spl/kstat/zfs/<pool>/txgs\fR
 .sp
-Default value: \fB0\fR.
+Default value: \fB100\fR.
 .RE
 
 .sp

diff --git a/module/zfs/spa_stats.c b/module/zfs/spa_stats.c
index 8c4dba29e26d23607477546d5f4e921c17471622..3eeb83a50b3dd9d4fa91282f26292895176b8bab 100644 (file)
--- a/module/zfs/spa_stats.c
+++ b/module/zfs/spa_stats.c
@@ -34,9 +34,9 @@ int zfs_read_history = 0;
 int zfs_read_history_hits = 0;
 
 /*
- * Keeps stats on the last N txgs, disabled by default.
+ * Keeps stats on the last 100 txgs by default.
  */
-int zfs_txg_history = 0;
+int zfs_txg_history = 100;
 
 /*
  * Keeps stats on the last N MMP updates, disabled by default.