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bphillips1
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March 13th, 2009 10:00
Dual Reading Capabilities in a CX3-40
Hello all,
I had a question regarding our CX3-40 and dual reading mirrored drives. I was doing some research on Fast Track Data Warehousing in SQL Server 2008 and I read the following paragraph on the MSDN website:
"Because of the read nature of typical data warehouse queries, these Fast Track reference configurations also take advantage of the storage arrays¿ dual reading capabilities. The EMC CX4-240 and the HP MSA-2000 can read from both drives in a mirror separately, which means the Fast Track reference architecture solutions rely on mirrored drives where the data is stored on two drives in case of a failure. One advantage these technologies provide is that they can answer I/O requests from both drives in a mirror without overlap. This capability almost doubles the I/O throughput of the LUNs."
My question is, does our CX3-40 have this capability?
I had a question regarding our CX3-40 and dual reading mirrored drives. I was doing some research on Fast Track Data Warehousing in SQL Server 2008 and I read the following paragraph on the MSDN website:
"Because of the read nature of typical data warehouse queries, these Fast Track reference configurations also take advantage of the storage arrays¿ dual reading capabilities. The EMC CX4-240 and the HP MSA-2000 can read from both drives in a mirror separately, which means the Fast Track reference architecture solutions rely on mirrored drives where the data is stored on two drives in case of a failure. One advantage these technologies provide is that they can answer I/O requests from both drives in a mirror without overlap. This capability almost doubles the I/O throughput of the LUNs."
My question is, does our CX3-40 have this capability?
- Expanding on what Allen wrote, the capability of sending reads to the mirrored set to be serviced rather than the primary drives all the time has been around for a while. Seeing the data is the same on the two drives (mirrored pair) we know we can go to either one to read the data, and the array will do this.
One extra thing to mention is that there is still only one view into the data. The capability of reading only from a certain location cannot be specified. The SP will decide where to read from based on outstanding IO to the drives.
-Ryan
Allen Ward
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Posted March 13th, 2009 12:00
What I can tell you now is that the capability for CLARiiON to simultaneously read from both disks in a mirrored pair goes way back (at least to the FC4700 and probably further). So as long as the technology doesn't require an specific optimization for it, then there is no reason an older CLARiiON shouldn't provide this functionality. I suspect they only mention the CX4 as the currently available product from EMC.