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https://issues.apache.org/jira/browse/DIRMINA-764?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13451104#comment-13451104
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Bernd Eckenfels commented on DIRMINA-764:
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There are two things here, in normal operation where the client is actually
receiving data the read/write should be balanced. However the danger of DOS by
overloading the write buffer (by a client which does not read and is able to
trigger more answeres) is a question of application design. Besides a capacity
limited write queue the future/sent callbacks can be used to monitor
outstanding writes. And another note: the write queue objects are much too
heavy in terms of overhead. It would be good if a simple application can only
enqeue iobuffers, and maybe have a simple integer sequence for
tracking/callbacks/futures.
> DDOS possible in only a few seconds...
> --------------------------------------
>
> Key: DIRMINA-764
> URL: https://issues.apache.org/jira/browse/DIRMINA-764
> Project: MINA
> Issue Type: Bug
> Affects Versions: 2.0.0-RC1
> Reporter: Emmanuel Lecharny
> Assignee: Emmanuel Lecharny
> Priority: Blocker
> Fix For: 2.0.6
>
> Attachments: screenshot-1.jpg, screenshot-2.jpg
>
>
> We can kill a server in just a few seconds using the stress test found in
> DIRMINA-762.
> If we inject messages with no delay, using 50 threads to do that, the
> ProtocolCodecFilter$MessageWriteRequest is stuffed with hundred of thousands
> messages waiting to be written back to the client, with no success.
> On the client side, we receive almost no messages :
> 0 messages/sec (total messages received 1)
> 2 messages/sec (total messages received 11)
> 8 messages/sec (total messages received 55)
> 8 messages/sec (total messages received 95)
> 9 messages/sec (total messages received 144)
> 3 messages/sec (total messages received 162)
> 1 messages/sec (total messages received 169)
> ...
> On the server side, the memory is totally swamped in 20 seconds, with no way
> to recover :
> Exception in thread "pool-1-thread-1" java.lang.OutOfMemoryError: Java heap
> space
> (see graph attached)
> On the server, ConcurrentLinkedQueue contain the messages to be written (in
> my case, 724 499 Node are present). There are also 361629
> DefaultWriteRequests, 361628 DefaultWriteFutures, 361625 SimpleBuffer, 361
> 618 ProtocolCodecFilter$MessageWriteRequest and 361 614
> ProtocolCodecFilter$EncodedWriteRequests.
> That mean we don't flush them to the client at all.
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