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From Jay Svc <jaytechg...@gmail.com>
Subject Re: How to make compaction run faster?
Date Wed, 17 Apr 2013 22:53:27 GMT
Hi Edward,

Thank you for response. I have tried the following -

1. I have tried various compaction throughput ranging from 16M to 1G. CPU
continued to be low and memory between 40% to 50%. I still see compaction
more backing.
2. Does concurrent compactors take effect with Leveled compaction? (yaml
says this parameter has no effect with LCS)
3. I have tried multi-threaded compaction as well I do not see change in
handling the compaction.
4. I have 24 core CPU, have RAID 10 disks and commitlog on SSD and 48GB or
RAM with 8GB Heap.

Thanks,
Jay


On Wed, Apr 17, 2013 at 3:26 PM, Edward Capriolo <edlinuxguru@gmail.com>wrote:

> three things:
> 1) compaction throughput is fairly low (yaml nodetool)
> 2) concurrent compactions is fairly low (yaml)
> 3) multithreaded compaction might be off in your version
>
> Try raising these things. Otherwise consider option 4.
>
> 4)$$$$$$$$$$$$$$$$$$$$$$$ RAID,RAM<CPU$$$$$$$$$$$$$$
>
>
> On Wed, Apr 17, 2013 at 4:01 PM, Jay Svc <jaytechgeek@gmail.com> wrote:
>
>> Hi Team,
>>
>>
>>
>> I have a high write traffic to my Cassandra cluster. I experience a very
>> high number of pending compactions. As I expect higher writes, The pending
>> compactions keep increasing. Even when I stop my writes it takes several
>> hours to finishing pending compactions.
>>
>>
>> My CF is configured with LCS, with sstable_size_mb=20M. My CPU is below
>> 20%, JVM memory usage is between 45%-55%. I am using Cassandra 1.1.9.
>>
>>
>> How can I increase the compaction rate so it will run bit faster to match
>> my write speed?
>>
>>
>> Your inputs are appreciated.
>>
>>
>> Thanks,
>>
>> Jay
>>
>>
>

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