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Flume >> mail # user >> NettyAvroRPCClient hangs Client JVM


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Re: NettyAvroRPCClient hangs Client JVM
Are you using the Memory Channel on the agents? We do know that there might be some issues when the memory channel is used when the heap is pretty large. We are wokring to resolve it.
Thanks,
Hari
On Friday, October 4, 2013 at 5:34 AM, Bhaskar V. Karambelkar wrote:

> We've a client JVM process which uses flume client SDK (NettyAvroRPCClient) to push events to a flume source which ultimately lands in HDFS.
>
> On production we're still on flume 1.3, and one thing we find consistently is that under heavy load, the client JVM hangs. We've narrowed it down to the Flume client SDK,  
>
> From what I suspect a long GC pause in flume agent, causes disconnects in avro client, which can lead to client JVM hangs.
>
> We're getting event's at the rate of about 25,000/sec, which are distributed across 8 clients, and they in turn forward them to 24 flume sources ( 6 boxes with 4 sources each). and each source writes to HDFS (i.e. 24 HDFS sinks as well).
>
> I tried switching flume agents GC to G1, which sort of helped, earlier the client JVM hangs were about 5 mins apart, now it's about 10 mins, so there is some progress.
>
> Question is how to completely eliminate these hangs. The hang is so bad, I can't even get the JVM to do a thread dump, so possible way for me to investigate what caused the JVM to hang.
>
> Could upgrading to 1.4, and using Thrift source help ?