Hi, Just wondering, Did you find something like this on your syslog ? %MGBL-NETFLOW-6-INFO_CACHE_SIZE_EXCEEDED : Cache size of 1000000 for monitor xxx has been exceeded
Regards, Jimmy Hng. On Tue, May 24, 2016 at 12:02 AM, Robert Williams <[email protected]> wrote: > Hi, > > Doing some more digging, found this from 2014: > > Netflow specific scale and Limitations are described below: > 1. Supports configurable Sampling Rate 1:1 ~ 1: 65535 > 2. Supports only up to 4 Sampling Rates (or Intervals) per Ethernet LC > LC; no such limit for Enhanced Ethernet LC. > 3. Up to 4k interfaces/sub-interfaces (4K system limitation) can be > configured with flow monitor per system. > 4. Supports up to 8 flow exporters per flow monitor > 5. Supports up to 1 million flow entries per LC > 6. Supports up to 50k flows per second with LC CPU usage up to 50% per > Ethernet LC LC > 7. Supports upto 100K flows per second with LC CPU usage up to 50% per > Enhanced Ethernet LC LC > 8. Netflow scale is increased to 200Kpps on Enhanced Ethernet LC based > LCs > 9. Supports exporting packet rates up to 50k flows per second (100K > flows per sec on Enhanced Ethernet LC based LCs) with LC CPU usage up to 50% > > "Irrespective of the rate at which the NP punts the records to CPU, > exporter picks up a maximum of 2000 records at a time from the cache that > are eligible for export (timers, network/TCP session events, etc). This is > basically to avoid NetIO dropping the packets due to lack of b/w. When the > exporter wakes up again, it repeats the same." > > So, it can collect 100k flows per second, but can only export 2k each time > it runs the exporter. The interval for the exporter is unclear however. > > I've also found out why this is such an issue on our 9001 but not on any > of our 900x larger chassis. Looks like on those the hardware punt is being > limited to 25kpps per NP because we have some BVIs with Netflow on them. > This causes it to distribute the rate limit for punting to ALL the NPs on > the LC, even when only two ports are involved in Netflow. Thus, it's > "sampled sampling" and so the rate of flow data is significantly lower than > the 9001 which is allowing all 100kpps on one NP which has 4 x 10G > interfaces punting into it. > > mmm... > > > > Robert Williams > Custodian Data Centre > Email: [email protected] > http://www.CustodianDC.com > > -----Original Message----- > From: Dale W. Carder [mailto:[email protected]] > Sent: 23 May 2016 16:02 > To: Robert Williams <[email protected]> > Cc: [email protected] > Subject: Re: [c-nsp] A9K Netflow export drops > > Thus spake Robert Williams ([email protected]) on Sat, May 21, 2016 > at 10:59:50AM +0000: > > > > I've got an issue on one of our smaller 9001 boxes which is puzzling me. > > It suffers from a high rate of netflow export drops (not cache drops) > shown here: > > > > So from what I understand, it is capturing the flows OK but is unable to > get the flow data out, for some reason. > > I can confirm that our 9k's suffer from this also. > > The last I checked you can export at the rate of 2000 flows/sec. I have > not > looked in 2 years or so to see if this limit was configurable yet. > > > So - what am I missing here? Surely with a cache capability of 1M it > should be ok to export flows when were are only around 30,000 of them > nicely ticking over? > > join the club. :-( > > Dale > _______________________________________________ > cisco-nsp mailing list [email protected] > https://puck.nether.net/mailman/listinfo/cisco-nsp > archive at http://puck.nether.net/pipermail/cisco-nsp/ > _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
