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Posted to user@hbase.apache.org by Hari Sreekumar <hs...@clickable.com> on 2010/11/30 05:31:15 UTC

ECC memory?

Hi,

   I read recently that ECC memory is better for HBase/Hadoop. But isn't ECC
memory slightly slower than normal memory? How much extra reliability does
ECC provide? Has anyone done a comparison of ECC vs normal memory stress
test of HBase or hadoop in general? It also costs more. Is it worth it?

Thanks,
Hari

Re: ECC memory?

Posted by Ryan Rawson <ry...@gmail.com>.
The link to the mail discussion is broken but here it is:

http://wiki.apache.org/hadoop/MachineScaling

"Hadoop benefits greatly from ECC memory, which is not low-end,
however using ECC memory is RECOMMENDED."

Generally speaking you can redo a map reduce task if it faults due to
ram issues, but you can't always redo a hbase operation.

-ryan

On Mon, Nov 29, 2010 at 11:58 PM, Christian van der Leeden
<ch...@googlemail.com> wrote:
> Hi,
>
>        I guess this is only reliability, since the read failures will be corrected
> but also reported, so you have a possibility to change the memory that is bad,
> Without ECC you get garbage or read failures (SIG 11 e.g.) and your node
> will be corrupted or down.
>
> Christian
>
> On Nov 30, 2010, at 5:31 AM, Hari Sreekumar wrote:
>
>> Hi,
>>
>>   I read recently that ECC memory is better for HBase/Hadoop. But isn't ECC
>> memory slightly slower than normal memory? How much extra reliability does
>> ECC provide? Has anyone done a comparison of ECC vs normal memory stress
>> test of HBase or hadoop in general? It also costs more. Is it worth it?
>>
>> Thanks,
>> Hari
>
>

Re: ECC memory?

Posted by Christian van der Leeden <ch...@googlemail.com>.
Hi,

	I guess this is only reliability, since the read failures will be corrected
but also reported, so you have a possibility to change the memory that is bad,
Without ECC you get garbage or read failures (SIG 11 e.g.) and your node
will be corrupted or down.

Christian

On Nov 30, 2010, at 5:31 AM, Hari Sreekumar wrote:

> Hi,
> 
>   I read recently that ECC memory is better for HBase/Hadoop. But isn't ECC
> memory slightly slower than normal memory? How much extra reliability does
> ECC provide? Has anyone done a comparison of ECC vs normal memory stress
> test of HBase or hadoop in general? It also costs more. Is it worth it?
> 
> Thanks,
> Hari