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From "Hiller, Dean" <>
Subject Re: index_interval file size is the same after modifying 128 to 512?
Date Tue, 26 Mar 2013 12:20:47 GMT
We only look at our program's response time at the high level and have a
scatter plot.  The scatter plot shows no real differences so even though
what you say may be true, our end users are not seeing any differences.  I
have not checked the any further because the high level use cases look


On 3/26/13 2:35 AM, "Michal Michalski" <> wrote:

>Dean, as I can see you are satisfied with the result of increasing ii
>from 128 to 512, didn't you observed any drawbacks of this change? I
>remember you mentioned no change in Read Latency and a significant drop
>of heap size, but did you check any other metrics?
>I did the opposite (512 -> 128; before we've had problems with heap
>size, now we can revert it, so I check if it makes sense) and I do not
>see almost any difference in Read Latency too, but I can see that the
>number of dropped READ messages has decreased significantly (it's 1 or
>even 2 orders of magnitude lower for the nodes I set ii = 128 comparing
>to the nodes with ii = 512; the exact value is about 0.005 / sec.
>comparing to about 0.01 - 0.2 for other nodes) and I have much less
>connection resets reported by netstat's Munin plugin. In other words, as
>I understand it - there's much less timeouts which should improve
>overall C* performance, even if I can't see it in read latency graph for
>CFs (unluckily I don't have a graph for StorageProxy latencies to easily
>check it).
>To make sure about the reason of this differences and its effect on C*
>performance, I'm looking for some "references" in other people's
>experience / observations :-)
>W dniu 22.03.2013 17:17, Hiller, Dean pisze:
>> I was just curious.  Our RAM has significantly reduced but the
>>*Index.db files are the same size size as before.
>> Any ideas why this would be the case?
>> Basically, Why is our disk size not reduced since RAM is way lower?  We
>>are running strong now with 512 index_interval for past 2-3 days and RAM
>>never looked better.  We were pushing 10G before and now we are 2G
>>slowing increasing to 8G before gc compacts the long lived stuff which
>>goes back down to 2G againĊ ..very pleased with LCS in our system!!!!!
>> Thanks,
>> Dean

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