Hello, I am trying to configure MRTG to monitor a number of routers and switches but so far I have encountered some problems.
This problem seems to be caused when MRTG is processing data for its log entry, it multiplies the data by 1000 which causes the entry to exceed the maximum bandwidth for a given interface and is therefore discarded by the MRTG logs. I understand the format of the MRTG log files is as follows: First line: <UNIX_time_in_seconds_since_epoch> <current_input_value_in_bytes> <current_output_value_in_bytes> Data: < UNIX_time_in_seconds_since_epoch> <input_during_time_interval_in_bytes> <input_average_in_bytes> <output_during_time_interval_in_bytes> <output_average_in_bytes> Initially no data was being recorded in the logs. After debugging MRTG I understand this was caused by the amount of data (input and output) exceeding the MaxBytes option. This option was correctly configured by cfgmaker for the interface bandwidth. By replacing this value with an insanely high value MRTG started recording data. I understand that MRTG (cfgmaker) calculates MaxBytes as follows: Interface speed 256Kbps (Kilo bits) 256 / 8 = 32KBps (Kilo Bytes) 32 * 1000 = 32000 B/s (Bytes per second) MaxBytes = 32000 However, data logged by MRTG seems to massively exceed this threshold. On further analysis, the following equation seems to be used by MRTG to calculate a log entry. ((current_input_value_in_bytes - previous_input_value_in_bytes) / time_interval) * 1K) = data entry Most of which makes sense except the last multiplication. Why multiply the data by 1000 when it is already in Bps? My mrtg.cfg test config file is as follows: RunAsDaemon:Yes Interval: 5 WorkDir: /mrtg-test Options[_]: bits,nobanner,growright Target[1.2.3.4_3]: 3:[EMAIL PROTECTED]: SetEnv[1.2.3.4_3]: MRTG_INT_IP="5.6.7.8" MRTG_INT_DESCR="Serial3/0" #MaxBytes[1.2.3.4_3]: 32000 MaxBytes[1.2.3.4_3]: 32000000 Title[1.2.3.4_3]: Traffic Analysis for 3 - host.domain.com Thanks in advance, Robin. Robin Butler Firewall and Network Engineer ioko Tel: 01904 438000 Mob: 07776 198142 Fax: 01904 435450 Email: [EMAIL PROTECTED] -- Unsubscribe mailto:[EMAIL PROTECTED] Archive http://www.ee.ethz.ch/~slist/mrtg FAQ http://faq.mrtg.org Homepage http://www.mrtg.org WebAdmin http://www.ee.ethz.ch/~slist/lsg2.cgi
