—The Gartner Dataquest market research firm estimates that disk drive manufacturers shipped slightly more than four million Serial Attached SCSI (SAS) drives last year—a number that is expected to triple to almost 12 million units this year. If those estimates hold true, shipments of SAS drives will eclipse shipments of Ultra320 SCSI drives later this year. Clearly, SAS drives have entered the mainstream.
Many end users wind up with SAS drives as part of their server purchases. In other words, they don't actually evaluate SAS against the primary alternatives, such as parallel SCSI or Fibre Channel drives.
That wasn't the case at Green City Cable TV (GCTV), a local TV station in Japan. Working in the high-definition (HD) format in its nonlinear editing operations, the TV station was experiencing the limitations of parallel SCSI. Using an Ultra320 SCSI-based disk array in a RAID-0 configuration to edit multiple HD video clips, GCTV was only able to run three HD video streams simultaneously without frame skips.
Fibre Channel arrays could handle the 1080i resolution and the 145Mbps data rate required for HD editing, but Fibre Channel subsystems proved relatively expensive for the TV station.
Working with system builder PFU, GCTV opted for a SAS-based JBOD array from Xtore with a SAS RAID card. Specifically, PFU integrated an LSI MegaRAID SAS 8480E RAID controller with a Hewlett-Packard XW8400 workstation connected to Xtore's 3U XJ-SA12-316R array. PFU configured the system as a RAID-5 array and populated it with 16 73GB, 15,000rpm SAS disk drives from Fujitsu.
With this configuration, GCTV was able to edit and review as many as 10 HD video streams simultaneously without any frame skips.
Xtore's 16-bay XJ-SA12-316R, which is part of the company's XJ 1100 series of SAS JBOD arrays, has a transfer rate of 1.2GBps per x4 connector and supports SAS and/or SATA drives. The SA12 configuration has a single I/O module, but an SA24 version has two I/O modules.
LSI's MegaRAID SAS 8480E is an 8-port (two x4 SAS connections) RAID controller with 3Gbps throughput per port. Based on an Intel IOP333 I/O processor and a PCI Express host bus, the 8480E comes with 256MB of cache memory. Configured with SAS expanders, the controller can support up to 122 SAS or SATA disk drives.
For more information on SAS, visit the SAS Resource Center, a sponsored "micro site."
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