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From Ryan Rawson <ryano...@gmail.com>
Subject Re: hbase/zookeeper
Date Fri, 17 Jul 2009 19:57:51 GMT
The ZK folks also recommend quorums of 5 nodes.  Said something about
diminishing returns at 7 and 9...

-ryan

On Fri, Jul 17, 2009 at 12:52 PM, Andrew Purtell<apurtell@apache.org> wrote:
> Thanks. That's good advice.
>
> We tune our heap allocations based on metrics collected over typical
> and peak usage cases.
>
>   - Andy
>
>
>
>
>
> ________________________________
> From: Jonathan Gray <jgray@apache.org>
> To: hbase-user@hadoop.apache.org
> Sent: Friday, July 17, 2009 12:42:30 PM
> Subject: Re: hbase/zookeeper
>
> ZK guys seem to say you should give it 1GB at least.
>
> This should not matter for 0.20.  In 0.21, our use of ZK will expand and it will need
more memory.  If you plan on using ZK for anything besides HBase, make sure you give it more
memory.  For now, you're probably okay with 256MB.
>
> Andrew Purtell wrote:
>> That looks good to me, in line with the best practices that are gelling as
>> we collectively gain operational experience.
>> This is how we allocate RAM on our 8GB worker nodes:
>>
>>   Hadoop
>>     DataNode     - 1 GB     TaskTracker  - 256 MB (JVM default)
>>     map/reduce tasks - 200 MB (Hadoop default)
>>
>>   HBase
>>     ZK           - 256 MB (JVM default)
>>     Master       - 1 GB (HBase default, but actual use is < 500MB)
>>     RegionServer - 4 GB
>>
>> We have a Master and hot spare Master each running on one of the workers.
>> Our workers are dual quad core so we have them configured for maximum
>> concurrent task execution of 4 mappers and 2 reducers and we run the
>> TaskTracker (therefore, also the tasks) with niceness +10 to hint to
>> the OS the importance of scheduling the DataNodes, ZK quorum peers, or
>> RegionServers ahead of them.
>> Note that the Hadoop NameNode is a special case which runs the NN in a
>> standalone configuration with block device level replication to a hot
>> spare configured in the typical HA fashion: heartbeat monitoring,
>> fencing via power control operations, virtual IP address and L3 fail
>> over, etc.
>> Also, not all nodes participate in the ZK ensemble. Some 2N+1 subset is
>> reasonable: 3, 5, 7, or 9. I expect that a 7 or 9 node ensemble can
>> handle 1000s of clients, if the quorum peers are running on dedicated
>> hardware. We are considering this type of deployment for the future.
>> However, for now we colocate ZK quorum peers with (some) HBase
>> regionservers.
>> Our next generation will use 32GB. This can support aggressive caching
>> and in memory tables.
>>    - Andy
>>
>>
>>
>>
>> ________________________________
>> From: Fernando Padilla <fern@alum.mit.edu>
>> To: hbase-user@hadoop.apache.org
>> Sent: Friday, July 17, 2009 10:30:52 AM
>> Subject: Re: hbase/zookeeper
>>
>> thank you!
>>
>> I'll pay attention to the CPU load then.  Any tips about the memory distribution?
 This is what I'm expecting, but I'm a newb. :)
>>
>> DataNode - 1.5G
>> TaskTracker - .5G
>> Zookeeper - .5G
>> RegionServer - 2G
>> M/R - 2G
>>
>>
>>
>
>
>

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