diff --git a/doc/rrd-beginners.pod b/doc/rrd-beginners.pod
index 644f2f005eacb43d0268db2f20cf0a778f8e32b1..f3c209bfa15b9f65d4d3a76fa703e70c80f478e9 100644 (file)
--- a/doc/rrd-beginners.pod
+++ b/doc/rrd-beginners.pod
=back
RRDtool is designed to store time series of data. With every data
-update, an assosiated time stamp is stored. Time is always expressed
-in seconds passed since epoch (01-01-1971). RRDtool can be installed
+update, an associated time stamp is stored. Time is always expressed
+in seconds passed since epoch (01-01-1970). RRDtool can be installed
on Unix as well as Windows. It comes with a command set to carry out
various operations on RRD databases. This command set can be accessed
from the command line, as well as from Shell or Perl scripts. The
This value is also called Primary Data Point B<(PDP)>. In our example
mentioned above, a new PDP is generated every 300 seconds.
-Note, that if you do NOT supply new datapoints exactly every 300 seconds,
+Note, that if you do NOT supply new data points exactly every 300 seconds,
this is not a problem, RRDtool will interpolate the data accordingly.
B<DST> (Data Source Type) defines the type of the DS. It can be
the previous value is greater than 0). Traffic counters on a router
are an ideal candidate for using COUNTER as DST. DERIVE is the same as
COUNTER, but it allows negative values as well. If you want to see the
-rate of I<change> in free diskspace on your server, then you might
+rate of I<change> in free disk space on your server, then you might
want to use the DERIVE data type. ABSOLUTE also saves the rate of
change, but it assumes that the previous value is set to 0. The
difference between the current and the previous value is always equal
other number which might also be a valid data value. For example, the
traffic flow counter on a router keeps increasing. Lets say, a value
is missed for an interval and 0 is stored instead of UNKNOWN. Now when
-hte next value becomes available, it will calculate the difference
+the next value becomes available, it will calculate the difference
between the current value and the previous value (0) which is not
correct. So, inserting the value UNKNOWN makes much more sense here.
# calculate the average of the array
my $tot_mem_ave = $tot_mem_sum/($count);
# create the graph
- RRDs::graph ("/images/mem_$count.png", \
- "--title= Memory Usage", \
- "--vertical-label=Memory Consumption (MB)", \
- "--start=$start_time", \
- "--end=$end_time", \
- "--color=BACK#CCCCCC", \
- "--color=CANVAS#CCFFFF", \
- "--color=SHADEB#9999CC", \
- "--height=125", \
- "--upper-limit=656", \
- "--lower-limit=0", \
- "--rigid", \
- "--base=1024", \
- "DEF:tot_mem=target.rrd:mem:AVERAGE", \
- "CDEF:tot_mem_cor=tot_mem,0,671744,LIMIT,UN,0,tot_mem,IF,1024,/",\
- "CDEF:machine_mem=tot_mem,656,+,tot_mem,-",\
- "COMMENT:Memory Consumption between $start_time",\
- "COMMENT: and $end_time ",\
- "HRULE:656#000000:Maximum Available Memory - 656 MB",\
- "AREA:machine_mem#CCFFFF:Memory Unused", \
+ RRDs::graph ("/images/mem_$count.png",
+ "--title= Memory Usage",
+ "--vertical-label=Memory Consumption (MB)",
+ "--start=$start_time",
+ "--end=$end_time",
+ "--color=BACK#CCCCCC",
+ "--color=CANVAS#CCFFFF",
+ "--color=SHADEB#9999CC",
+ "--height=125",
+ "--upper-limit=656",
+ "--lower-limit=0",
+ "--rigid",
+ "--base=1024",
+ "DEF:tot_mem=target.rrd:mem:AVERAGE",
+ "CDEF:tot_mem_cor=tot_mem,0,671744,LIMIT,UN,0,tot_mem,IF,1024,/",
+ "CDEF:machine_mem=tot_mem,656,+,tot_mem,-",
+ "COMMENT:Memory Consumption between $start_time",
+ "COMMENT: and $end_time ",
+ "HRULE:656#000000:Maximum Available Memory - 656 MB",
+ "AREA:machine_mem#CCFFFF:Memory Unused",
"AREA:tot_mem_cor#6699CC:Total memory consumed in MB");
my $err=RRDs::error;
if ($err) {print "problem generating the graph: $err\n";}