Actually, I have a question about the new logs you sent. Have you tried to 
clean up the state of bookies before rerunning them or these logs correspond to 
a bookie that you're bringing back up and the bookie is trying to read its old 
state? If it is the latter, then I would suggest to give it a fresh start. 

-Flavio

On Apr 5, 2012, at 4:53 PM, John Nagro wrote:

> Flavio -
> 
> I really appreciate your prompt response. Some quick background - we use some 
> of the hadoop technologies for storage, coordination, and processing. 
> Recently we wanted to add a write-ahead-log to our infrastructure so that 
> clients could record "transactions" prior to executing them - such as updates 
> going to an API or processing of an event. I've written a set of tools that 
> use BK as a generic write-ahead-logger. Clients (using zookeeper for 
> coordination) can create named write ahead logs with custom chunking (how 
> frequently a new ledger is created - based on size/time). Once a ledger has 
> rolled-over (or a client crashes), a persister (monitoring ZK) reads that 
> ledger and persists it to S3/HDFS as hadoop sequence files where a map-reduce 
> process can reconcile it. The ledger is then deleted from BK. This is all 
> done using ZK in a fashion where (hopefully) once a client has written any 
> data to the ledger it will always end up on S3/HDFS (via BK) even if the 
> client crashes (the persister will always know which ledger belongs to which 
> log and which ledgers are currently in use).
> 
> Does that sound like an appropriate use of BK? It seemed like a natural fit 
> as a durable storage solution until something can reliably get it to a place 
> where it would ultimately be archived and could be reprocessed/reconciled 
> (S3/HDFS).
> 
> As for the bug fix you mentioned, this gist shows the logs from the cut i 
> made this morning:
> 
> https://gist.github.com/aea874d89b28d4cfef31
> 
> As you can see, there are still some exceptions and error messages that 
> repeat (forever). This is the newest cut available on github, last commit is:
> 
> commit f694716e289c448ab89cab5fa81ea0946f9d9193
> Author: Flavio Paiva Junqueira <[email protected]>
> Date:   Tue Apr 3 16:02:44 2012 +0000
> 
> BOOKKEEPER-207: BenchBookie doesn't run correctly (ivank via fpj)
> 
> git-svn-id: 
> https://svn.apache.org/repos/asf/zookeeper/bookkeeper/trunk@1309007 
> 13f79535-47bb-0310-9956-ffa450edef68
> 
> 
> What are your thoughts? Thanks!
> 
> -John
> 
> 
> On Thu, Apr 5, 2012 at 10:10 AM, Flavio Junqueira <[email protected]> wrote:
> Hi John, Let's see if I can help:
> 
> On Apr 5, 2012, at 3:19 PM, John Nagro wrote:
> 
>> Hello -
>> 
>> I've been hitting Ivan up for advice about a bookkeeper project of mine. I 
>> recently ran into another issue and he suggested I inquire here since he is 
>> traveling.
>> 
>> We've got a pool of 5 BK servers running in EC2. Last night they got into a 
>> funky state and/or crashed - unfortunately the log with the original event 
>> got rotated (that has been fixed). I was running a cut of 4.1.0-SNAPSHOT sha 
>> 6d56d60831a63fe9520ce156686d0cb1142e44f5 from Wed Mar 28 21:57:40 2012 +0000 
>> which brought everything up to BOOKKEEPER-195. That build had some bugfixes 
>> over 4.0.0 that I was originally running (and a previous version before 
>> that).
>> 
> 
> Is there anything else you can say about your application, like how fast 
> you're writing and how often you're rolling ledgers maybe? Are you deleting 
> ledgers at all?
> 
> 
>> When I restart the servers after the incident this is what the logs looked 
>> like:
>> 
>> https://gist.github.com/f2b9c8c76943b057546e
>> 
>> Which contain a lot of errors - although it appears the servers come up (i 
>> have not tried to use the servers yet). Although I don't have the original 
>> stack that caused the crash, the logs from recently after the crash 
>> contained a lot of this stack:
>> 
>> 2012-04-04 21:04:58,833 - INFO  
>> [GarbageCollectorThread:GarbageCollectorThread@266] - Deleting entryLogId 4 
>> as it has no active ledgers!
>> 2012-04-04 21:04:58,834 - ERROR [GarbageCollectorThread:EntryLogger@188] - 
>> Trying to delete an entryLog file that could not be found: 4.log
>> 2012-04-04 21:04:59,783 - WARN  [NIOServerFactory-3181:NIOServerFactory@129] 
>> - Exception in server socket loop: /0.0.0.0
>> 
>> java.util.NoSuchElementException
>>         at java.util.LinkedList.getFirst(LinkedList.java:109)
>>         at 
>> org.apache.bookkeeper.bookie.LedgerCacheImpl.grabCleanPage(LedgerCacheImpl.java:458)
>>         at 
>> org.apache.bookkeeper.bookie.LedgerCacheImpl.putEntryOffset(LedgerCacheImpl.java:165)
>>         at 
>> org.apache.bookkeeper.bookie.LedgerDescriptorImpl.addEntry(LedgerDescriptorImpl.java:93)
>>         at 
>> org.apache.bookkeeper.bookie.Bookie.addEntryInternal(Bookie.java:999)
>>         at org.apache.bookkeeper.bookie.Bookie.addEntry(Bookie.java:1034)
>>         at 
>> org.apache.bookkeeper.proto.BookieServer.processPacket(BookieServer.java:359)
>>         at 
>> org.apache.bookkeeper.proto.NIOServerFactory$Cnxn.readRequest(NIOServerFactory.java:315)
>>         at 
>> org.apache.bookkeeper.proto.NIOServerFactory$Cnxn.doIO(NIOServerFactory.java:213)
>>         at 
>> org.apache.bookkeeper.proto.NIOServerFactory.run(NIOServerFactory.java:124)
> 
> This looks like what we found and resolved here:
> 
>       https://issues.apache.org/jira/browse/BOOKKEEPER-198
> 
>> 
>> This morning I upgraded to the most recent cut - sha 
>> f694716e289c448ab89cab5fa81ea0946f9d9193 made on Tue Apr 3 16:02:44 2012 
>> +0000 and restarted. That did not seem to correct matters, although the log 
>> has slightly different error messages:
>> 
>> https://gist.github.com/aea874d89b28d4cfef31
>> 
>> Does anyone know whats going on? How i can correct these errors? Are the 
>> machines in an okay state to use?
> 
> It sounds like we have resolved it in 198, so if you're using a recent cut, 
> you shouldn't observe this problem anymore. But, if it does happen again, it 
> would be great to try to find a way to reproduce it so that we can track the 
> bug... assuming it is a bug.
> 
> -Flavio
> 
> 
> 

flavio
junqueira
senior research scientist
 
[email protected]
direct +34 93-183-8828
 
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