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Flow Volume - from Cisco Device
Cisco devices will tell you the number of flows currently exported, no matter if they were successfully received by a server or not. This can be very useful to help calculate the amount of flow data that will come from a device before sending the flows to an opFlow server.
- Get the current time
- Get the number of flows
- Wait 2 minutes
- Get the current time
- Get the number of flows
- Do some math, subtract second flow number from first flow number, that is the number of flows for 2 minutes, divide by 120 and you have the number per second.
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router> show clock
11:57:51.155 AEST Wed Apr 2 2014 |
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router>sh ip flow export
Flow export v9 is enabled for main cache
Export source and destination details :
VRF ID : Default
Destination(1) 192.168.1.7 (12345)
Destination(2) 192.168.1.42 (12345)
Version 9 flow records
25716317 flows exported in 890127 udp datagrams
0 flows failed due to lack of export packet
0 export packets were sent up to process level
0 export packets were dropped due to no fib
1 export packets were dropped due to adjacency issues
0 export packets were dropped due to fragmentation failures
0 export packets were dropped due to encapsulation fixup failures |
So 25716317 have been sent. Now wait 2 minutes, then get the time again
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router>show clock
11:59:53.155 AEST Wed Apr 2 2014
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Now get the number of flows again:
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meatball>sh ip flow export
Flow export v9 is enabled for main cache
Export source and destination details :
VRF ID : Default
Destination(1) 192.168.1.7 (12345)
Destination(2) 192.168.1.42 (12345)
Version 9 flow records
25717645 flows exported in 890173 udp datagrams
0 flows failed due to lack of export packet
0 export packets were sent up to process level
0 export packets were dropped due to no fib
1 export packets were dropped due to adjacency issues
0 export packets were dropped due to fragmentation failures
0 export packets were dropped due to encapsulation fixup failures
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Figure out flows / 2 min or flows / second:
25717645 flows - 25716317 flows = 1328 flows / 2 min1328 / 120 = 11 flows / secondThe numbers you see will likely be higher, this is just an example. Please contact support@opmantek.com if you would like help correctly sizing your server.
Flow Volume - received by opFlow
opflow_stats.pl calculates how many flows per second are being received by the server. To view this info just run it
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