Document the maximum number of files in a ring buffer, including a warning about using large numbers of files.

svn path=/trunk/; revision=32999

1 files changed, 19 insertions, 11 deletions

diff --git a/doc/dumpcap.pod b/doc/dumpcap.pod
index 292d52adde..220d099728 100644
--- a/doc/dumpcap.pod
+++ b/doc/dumpcap.pod
@@ -58,14 +58,16 @@ Specify a criterion that specifies when B<Dumpcap> is to stop writing
 to a capture file.  The criterion is of the form I<test>B<:>I<value>,
 where I<test> is one of:
 
-B<duration>:I<value> Stop writing to a capture file after I<value> seconds have elapsed.
+B<duration>:I<value> Stop writing to a capture file after I<value> seconds have
+elapsed.
 
-B<filesize>:I<value> Stop writing to a capture file after it reaches a size of I<value>
-kilobytes (where a kilobyte is 1024 bytes). If this option
-is used together with the -b option, dumpcap will stop writing to the
-current capture file and switch to the next one if filesize is reached.
+B<filesize>:I<value> Stop writing to a capture file after it reaches a size of
+I<value> kilobytes (where a kilobyte is 1024 bytes). If this option is used
+together with the -b option, dumpcap will stop writing to the current capture
+file and switch to the next one if filesize is reached.
 
-B<files>:I<value> Stop writing to capture files after I<value> number of files were written.
+B<files>:I<value> Stop writing to capture files after I<value> number of files
+were written.
 
 =item -b  E<lt>capture ring buffer optionE<gt>
 
@@ -94,10 +96,16 @@ B<filesize>:I<value> switch to the next file after it reaches a size of
 I<value> kilobytes (where a kilobyte is 1024 bytes).
 
 B<files>:I<value> begin again with the first file after I<value> number of
-files were written (form a ring buffer).  This option requires either
-B<duration> or B<filesize> to be specified to control when to go to the next
-file.  It should be noted that each B<-b> parameter takes exactly one criterion;
-to specify two criterion, each must be preceded by the B<-b> option.
+files were written (form a ring buffer).  This value must be less than 100000.
+Caution should be used when using large numbers of files: some filesystems do
+not handle many files in a single directory well.  The B<files> criterion
+requires either B<duration> or B<filesize> to be specified to control when to
+go to the next file.  It should be noted that each B<-b> parameter takes exactly
+one criterion; to specify two criterion, each must be preceded by the B<-b>
+option.
+
+Example: B<-b filesize:1024 -b files:5> results in a ring buffer of five files
+of size one megabyte.
 
 =item -B  E<lt>capture buffer sizeE<gt>
 
@@ -192,7 +200,7 @@ link types can be used for the B<-y> option.
 
 =item -M
 
-When used with B<-D>, B<-L> and B<-S>, print machine-readable output. 
+When used with B<-D>, B<-L> and B<-S>, print machine-readable output.
 The machine-readable output is intended to be read by B<Wireshark> and
 B<TShark>; its format is subject to change from release to release.