Q: Why didn't Sun include controller-based data replication capability on the SE6920? A: Controller-based data replication capability is scheduled for release in the Sun StorEdge 6920 System in the first quarter of 2005. Q: You talk more about small I/Os that are common for financial and web-based transactions. How does the 6920 fare with typically large I/Os common in the oil and gas, data acquisition, and entertainment industries? A: You are right: we do speak a lot about IOPS (input/output operations per second) which typically are small read or write transactions of 512 byte to 8 Kbyte in size. These small transactions typically originate from financial/transactional applications and are random in nature. The StorEdge 6920 architecture is optimized for this sort of application. At the other end of the IO spectrum we have 'streaming' applications. Such applications are typically characterized by large IOs of 512 Kbyte to 1 Mbyte, with the disk access being sequential in nature. Editing of a large modern Hollywood movie with lots of digitized content is a good example of this sort of application. Scientific applications such as oil and gas exploration also generate large data sets at a clip and are another good example. Storage deployments optimized for streaming perform best with as much raw disk access as possible. Large switched JBOD farms with a SAN-based file system -- like Sun StorEdge QFS software -- are deployed to facilitate both spindle aggregation as well as the highest to-disk streaming performance. A modern disk drive can stream data at roughly 60 Mbyte/second, so it does not take very many drives to saturate the 400 MB backplane of a Fibre Channel JBOD (400/60 => 7 drives). The host side also needs to be optimized for streaming wherefore multiple hosts are typically used in parallel to archive the desired streaming performance. When it is desirable to RAID protect the data being streamed, the SAN switch is connected to a storage pool made up of multiple dual RAID controller-based systems -- such as the Sun StorEdge 3510 array. With an internal streaming capability of 800 MB/sec, the StorEdge 6920 is not optimized for streaming but for random IO. To get say 1600 MB/sec of streaming capability, you should look at a 16-port fabric switch and then 8 JBOD or 8 StorEdge 3510 arrays with Sun StorEdge QFS across 8 hosts. |
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