ISS Technology Update Volume 8, Number 7

ISS Technology Update Volume 8, Number 7
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SSD Performance
HP 3Gb/s SATA SSD read and write performance is significantly improved over first-generation SSDs, as shown in Table 1.
The new SSDs are particularly appropriate for applications that require storage systems capable of performing large numbers
of random reads per second. Traditionally, solutions designers have used RAID configurations with large numbers of disk drives
to achieve this. Using the new HP solid state drives, a single SSD can deliver two to six times as many random reads per
second (IOPs) as an entire RAID 0 array of 12 SAS disk drives. This makes the new drives ideal for read-intensive, high-IOPs
applications that do not require the large storage capacities that RAID configurations can offer.
Table 1. Performance comparison of SATA/SAS drives with SSDs for servers
6 Gb/s SAS drive 1st generation
HP SATA SSDs
2
nd
generation
HP 3Gb/s SATA SSDs
HP SAS SSDs
(preliminary)
Class Enterprise Midline Midline Enterprise
Interconnects 6 Gb/s SAS-2 1.5 Gb/s SATA 3.0 Gb/s SATA 6 Gb/s SAS-2 Dual Port
Write performance
sustained throughput
150 MB/s
@ 64 KB
50 MB/s 180 MB/s TBD
Write performance
random IO/s
285
(4 KB, Queue=16)
100 5000+ TBD
Read performance
sustained throughput
90 MB/s 100 MB/s 230 MB/s 560 MB/s
Read performance
random IO/s
340
(4 KB, Queue=16)
4300 20,000+ Up to 100,000
HP SSD futures
The new HP 3Gb/s SATA SSDs are the first SSD products designed to operate across most of the ProLiant server line. They
continue to use the more robust single-level cell NAND flash technology and are suitable for use in Midline (MDL) drive
environments where unconstrained workloads and a 100% duty cycle are not required. The NAND flash memory used in SSDs
has a limited life cycle for writes. Although advanced techniques such as wear-leveling and over-provisioning are used to help
overcome this, HP 3G SATA SSDs are still better suited for read-intensive environments where writes are 30% or less of the total
IO load.
SSD technology is still rapidly evolving. HP hopes to introduce its first Enterprise class SAS SSDs in 2010. These drives will be
engineered for unconstrained read and write workloads and 100% duty cycles. This will match the basic reliability
characteristics of Enterprise class disk drives while providing the IO performance advantages of SSDs. HP may also introduce
server SSDs based on multi-level cell NAND flash memory. These products will provide a solution for application environments
that need higher capacity SSDs, but do not require support for unconstrained IO workloads.
Additional resources
For additional information on the topics discussed in this article, visit the following websites:
Resource URL
HP Solid State Storage
www.hp.com/go/solidstate
Technology brief - Solid state drive technology for
ProLiant servers
http://h20000.www2.hp.com/bc/docs/support/SupportMa
nual/c01580706/c01580706.pdf
HP ProLiant drives (including solid state drives)
www.hp.com/products/harddiskdrives