Explain 'zfs list -t snap -o name -s name' speedup

Commit 0cee240 from FreeBSD dramatically speeds up 'zfs list'
performance assuming you're only interested in the dataset
names.  This optimization should be mentioned in the man page
to allow end users to take advantage of it.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1847

diff --git a/man/man8/zfs.8 b/man/man8/zfs.8
index 60a11a57ea0f994cb61412283281dfaa4bb56183..61b2eb287dc204d85a711c52ae148144efa2b816 100644 (file)
--- a/man/man8/zfs.8
+++ b/man/man8/zfs.8
@@ -1810,7 +1810,7 @@ Recursively rename the snapshots of all descendent datasets. Snapshots are the o
 .ad
 .sp .6
 .RS 4n
-Lists the property information for the given datasets in tabular form. If specified, you can list property information by the absolute pathname or the relative pathname. By default, all file systems and volumes are displayed. Snapshots are displayed if the \fBlistsnaps\fR property is \fBon\fR (the default is \fBoff\fR) . The following fields are displayed, \fBname,used,available,referenced,mountpoint\fR.
+Lists the property information for the given datasets in tabular form. If specified, you can list property information by the absolute pathname or the relative pathname. By default, all file systems and volumes are displayed. Snapshots are displayed if the \fBlistsnaps\fR property is \fBon\fR (the default is \fBoff\fR). When listing hundreds or thousands of snapshots performance can be improved by restricting the output to only the name.  In that case, it is recommended to use \fB-o name -s name\fR. The following fields are displayed by default, \fBname,used,available,referenced,mountpoint\fR.
 .sp
 .ne 2
 .mk