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Going the SAS Storage Way
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Adaptec SANbloc S50 JBOD

SANbloc S50 is an enterprise level 12-drive 2U rack mount solution for SAS controllers. This is probably the best example of enterprise scale SAS applications. The 12 drives may be either SAS or SATA drives, or a mixture of both. The included expander logic uses one or two SAS quad links to hook the S50 up to your host adapter or RAID controller. It is obvious that we are talking about a professional solution as it is based on two redundant power supply units with independent power inlets.

If you're already using an Adaptec SAS host adapter, you will be happy to hear that you can actually use the Adaptec Storage Manager to control the S50 and its drives. Using SATA hard drives at 500 GB each, the maximum of 12 drives will result in 6 TB of storage space, while 300 GB SAS drives will result in 3.6 TB. At two quad SAS links to the host adapter, the bandwidth is 2.4 GB/s, which should definitely be more than enough for any type of array. Putting all 12 drives into a RAID 0 array would result in maximum transfer rates of around 1.1 GB/s. A slightly different version with two independent SAS I/O modules will be available in the middle of this year.

The unit includes automatic temperature monitoring and includes automatic fan speed control. Yet, it was noisy enough for us to ban it from our offices after our tests were completed. Drive failure is communicated to the controller via SES-2 (SCSI Enclosure Services) or over a physical I2C interface.

Different from drive operating environment temperatures (41-131°F or 5-55°C), the enclosure may operate in between 32-104°F (0 and 40°C).

At the beginning of our tests, we reached burst transfer speeds of only 610 MB/s only. After changing the interface cable between the S50 and the Adaptec host controller, we finally managed to hit 760 MB/s. We found seven hard drives to saturate the system in RAID 0. Adding more drives would not allow for higher throughput.

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  • 0 Hide
    wdanforth , September 10, 2008 2:52 AM
    Thank you for the SAS lesson.
  • 0 Hide
    vinay_20 , December 12, 2011 11:44 AM
    It was a nice jest for SAS.