Guys,

Trying to benchmark on AWS is a waste of time. You end up chasing ghosts.
You want to benchmark, you need to isolate your systems to reduce extraneous 
factors.

You need real hardware, real network in a controlled environment.


Sent from a remote device. Please excuse any typos...

Mike Segel

> On Jan 16, 2014, at 12:34 PM, "Bryan Beaudreault" <[email protected]> 
> wrote:
> 
> This might be better on the user list? Anyway..
> 
> How many IPC handlers are you giving?  m1.xlarge is very low cpu.  Not only
> does it have only 4 cores (more cores allow more concurrent threads with
> less context switching), but those cores are severely underpowered.  I
> would recommend at least c1.xlarge, which is only a bit more expensive.  If
> you happen to be doing heavy GC, with 1-2 compactions running, and with
> many writes incoming, you are quickly using up quite a bit of CPU.  What is
> the load and CPU usage, on the 10.38.106.234:50010?
> 
> Did you see anything about blocking updates in the hbase logs?  How much
> memstore are you giving?
> 
> 
>> On Thu, Jan 16, 2014 at 1:17 PM, Andrew Purtell <[email protected]> wrote:
>> 
>> On Wed, Jan 15, 2014 at 5:32 PM,
>> Vladimir Rodionov <[email protected]> wrote:
>> 
>>> Yes, I am using ephemeral (local) storage. I found that iostat is most of
>>> the time idle on 3K load with periodic bursts up to 10% iowait.
>> 
>> Ok, sounds like the problem is higher up the stack.
>> 
>> I see in later emails on this thread a log snippet that shows an issue with
>> the WAL writer pipeline, one of the datanodes is slow, sick, or partially
>> unreachable. If you have uneven point to point ping times among your
>> cluster instances, or periodic loss, it might still be AWS's fault,
>> otherwise I wonder why the DFSClient says a datanode is sick.
>> 
>> --
>> Best regards,
>> 
>>   - Andy
>> 
>> Problems worthy of attack prove their worth by hitting back. - Piet Hein
>> (via Tom White)
>> 

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