I have no input on the specific issue you’re encountering, but a pattern we 
have seen to reduce the overhead of multiple remote input ports being required 
is to use a “central” remote input port and immediately follow it with a 
RouteOnAttribute to distribute specific flowfiles to the appropriate downstream 
flow / process group. Whatever sends data to this port can use an 
UpdateAttribute to add some “tracking/routing” attribute on the flowfiles 
before being sent. Inserting Merge/Split will likely affect your timing due to 
waiting for bins to fill, depending on your volume. S2S is pretty good at 
transmitting data on-demand with low overhead on one port; it’s when you have 
many remote input ports that there is substantial overhead. 


Andy LoPresto
[email protected]
[email protected]
PGP Fingerprint: 70EC B3E5 98A6 5A3F D3C4  BACE 3C6E F65B 2F7D EF69

> On Feb 6, 2020, at 2:34 PM, Elli Schwarz <[email protected]> 
> wrote:
> 
> We ran that command - it appears the site-to-sites that are causing the 
> issue. We had a lot of remote process groups that weren't even being used (no 
> data was being sent to that part of the dataflow), yet when running the lsof 
> command they each had a large number of open files - almost 2k! - showing 
> CLOSE_WAIT. Again, there were no flowfiles being sent to them, so can it be 
> some kind of bug that keeping a remote process group open is somehow opening 
> files and not closing them? (BTW, the reason we had to upgrade from 1.9.2 to 
> 1.11.0 was because we had upgraded our Java version and that cause an 
> IllegalBlockingModeException - is it possible that whatever fixed that 
> problem is now causing an issue with open files?)
> 
> We now disabled all of the unused remote process groups. We still have 
> several remote process groups that we are using so if this is the issue it 
> might be difficult to avoid, but at least we decreased the number of remote 
> process groups we have. Another approach we are trying is a merge content 
> before we send to the Nifi having the most issues, to have fewer flow files 
> sent at once site to site, and then splitting them after they are received.
> Thank you!
> 
>    On Thursday, February 6, 2020, 2:19:48 PM EST, Mike Thomsen 
> <[email protected]> wrote:  
> 
> Can you share a description of your flows in terms of average flowfile size, 
> queue size, data velocity, etc.?
> Thanks,
> Mike
> 
> On Thu, Feb 6, 2020 at 1:59 PM Elli Schwarz 
> <[email protected]> wrote:
> 
>  We seem to be experiencing the same problems. We recently upgraded several 
> of our Nifis from 1.9.2 to 1.11.0, and now many of them are failing with "too 
> many open files". Nothing else changed other than the upgrade, and our data 
> volume is the same as before. The only solution we've been able to come up 
> with is to run a script to check for this condition and restart the Nifi. Any 
> other ideas?
> Thank you!
> 
>     On Sunday, February 2, 2020, 9:11:34 AM EST, Mike Thomsen 
> <[email protected]> wrote:  
> 
>  Without further details, this is what I did to see if it was something
> other than the usual issue of having not enough file handlers available.
> Something like a legitimate case of someone forgetting to close file
> objects or something in the code itself.
> 
> 1. Setup a 8core/32GB VM on AWS w/ Amazon AMI.
> 2. Pushed 1.11.1RC1
> 3. Pushed the RAM settings to 6/12GB
> 4. Disabled flowfile archiving because I only allocated 8GB of storage.
> 5. Setup a flow that used 2 generateflow instances to generate massive
> amounts of garbage data using all available cores. (All queues were setup
> to hold 250k flow files)
> 6. Kicked it off and let it run for probably about 20 minutes.
> 
> No apparent problem with closing and releasing resources here.
> 
> On Sat, Feb 1, 2020 at 8:00 AM Joe Witt <[email protected]> wrote:
> 
>> these are usually very easy to find.
>> 
>> run lsof -p pid.  and share results
>> 
>> 
>> thanks
>> 
>> On Sat, Feb 1, 2020 at 7:56 AM Mike Thomsen <[email protected]>
>> wrote:
>> 
>>> 
>>> 
>> https://stackoverflow.com/questions/59991035/nifi-1-11-opening-more-than-50k-files/60017064#60017064
>>> 
>>> No idea if this is valid or not. I asked for clarification to see if
>> there
>>> might be a specific processor or something that is triggering this.
>>> 
>> 
>   

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