Update iostat manual page: Fix a small inaccuracy regarding %util field

iostat manual page used to say that device saturation occured when the
value of %util was close to 100%. This is true for devices serving
requests serially but not necessariyl for devices able to serve multiple
requests simultaneously. So update iostat manual page accordingly.

diff --git a/man/iostat.in b/man/iostat.in
index fc1dcc34a79206c9f379dcb252304061053de4c0..7a01af0856be10236d11476a9051df25f1b2525f 100644 (file)
--- a/man/iostat.in
+++ b/man/iostat.in
@@ -1,4 +1,4 @@
-.TH IOSTAT 1 "NOVEMBER 2012" Linux "Linux User's Manual" -*- nroff -*-
+.TH IOSTAT 1 "JULY 2013" Linux "Linux User's Manual" -*- nroff -*-
 .SH NAME
 iostat \- Report Central Processing Unit (CPU) statistics and input/output
 statistics for devices and partitions.
@@ -268,7 +268,9 @@ This field will be removed in a future sysstat version.
 .RS
 Percentage of CPU time during which I/O requests were issued to the device
 (bandwidth utilization for the device). Device saturation occurs when this
-value is close to 100%.
+value is close to 100% for devices serving requests serially.
+But for devices serving requests in parallel, such as RAID arrays and
+modern SSDs, this number does not reflect their performance limits.
 .RE
 .RE
 .SH OPTIONS