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From Jitendra Kumar Singh <jksingh26...@gmail.com>
Subject Re: HDFS using SAN
Date Thu, 18 Oct 2012 13:48:44 GMT

In the NetApp whitepaper on SAN solution (link given by Kevin) it makes
following statement. Can someone please elaborate (or give a link that
explains) how 12-disk in SAN can give 2000 IOPS while if used as JBOD would
give 600 IOPS?

"The E2660 can deliver up to 2,000 IOPS
from a 12-disk stripe (the bottleneck being the 12 disks). This headroom
translates into better read times
for those 64KB blocks. Twelve copies of 12 MapReduce jobs reading from 12
SATA disks can at best
never exceed 12 x 50 IOPS, or 600 IOPS. The E2660 volume has five times the
IOPS headroom, which
translates into faster read times and high MapReduce throughput "

Thanks and Regards,
Jitendra Kumar Singh

On Thu, Oct 18, 2012 at 6:02 PM, Luca Pireddu <pireddu@crs4.it> wrote:

> On 10/18/2012 02:21 AM, Pamecha, Abhishek wrote:
>> Tom
>> Do you mean you are using GPFS instead of HDFS? Also, if you can share,
>> are you deploying it as DAS set up or a SAN?
>> Thanks,
>> Abhishek
> Though I don't think I'd buy a SAN for a new Hadoop cluster, we have a SAN
> and are using it *instead of HDFS* with a small/medium Hadoop MapReduce
> cluster (up to 100 nodes or so, depending on our need).  We still use the
> local node disks for intermediate data (mapred local storage).  Although
> this set-up does limit our possibility to scale to a large number of nodes,
> that's not a concern for us.  On the plus, we gain the flexibility to be
> able to share our cluster with non-Hadoop users at our centre.
> --
> Luca Pireddu
> CRS4 - Distributed Computing Group
> Loc. Pixina Manna Edificio 1
> 09010 Pula (CA), Italy
> Tel: +39 0709250452

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