A Closer Look at the RamSan-710

Performance
Performance is key to a quality SSD. The RamSan-710 is the latest SSD from TMS,
maintaining the RamSan line’s position as the World’s Fastest Storage®. The
RamSan-710 boasts the following key performance metrics:
35 microsecond access time (writes)
175 microsecond access time (reads)
400,000 sustained random IOPS (writes)
400,000 sustained random IOPS (reads)
5 GB/second peak bandwidth
The key measure of the RamSan-710’s capabilities is its ability to sustain extreme
inputs/outputs per second (IOPS) even with mixed read/write workloads. This is
important because most applications have a mixture of reads and writes with a
great deal of random access. Most other Flash SSDs and hard disk drive (HDD)
solutions suffer significant performance degradation from either random access
patterns or write accesses, if not both. For example, most Flash SSDs suffer
disproportionately if they experience even a small percentage of writes, to the point
that their mixed read/write performance may actually be dramatically less than
their peak write performance. In practice, this means that a RamSan-710 will deliver
better sustained “real world” random read/write application performance than any
other Flash SSD.
And if other Flash SSDs have difficulty competing with the performance of the
RamSan-710, hard disk drives can’t even get in the ballpark. Consider this: high
performance 15K RPM Fibre Channel (FC) HDDs can achieve at best 300 IOPS. At
that IOPS rate, it would take well over 1,300 HDDs to equal the performance of one
RamSan-710. This means almost 100 disk enclosures in seven racks, all of which
would draw over 16,000 watts, while one RamSan-710 uses 280!
You can also compare HDD to the RamSan-710 on the basis of capacity and
performance. The highest-performing 15K RPM FC HDDs usually provide 146 GB of
capacity. One disk enclosure would offer 2 TB of “raw” storage, but deploying these
drives in RAID 10 sets for performance and reliability would actually offer only 1 TB
of usable capacity for each 3U 14 drive disk enclosure. To equal the RamSan-710’s
5 TB capacity you would need five of these enclosures and 70 disks. Combined with
the controller (another 3U), the full disk solution would require 18U (half a rack),
draw around 2,000 watts, and provide only a few percent of the performance of the
RamSan-710. Perhaps most surprisingly, if you include the power, space, and cooling
costs with the upfront acquisition costs of a disk controller with 70 disks, the
RamSan-710 may be the LESS expensive solution.
July 2011 8 Texas Memory Systems