Understanding endurance and performance characteristics of HP solid state drives

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on the card rather than the much faster SDRAM on the memory module. This significantly affects
command latency and overall storage performance.
SATA versus SAS SSD performance
HP offers both SATA and SAS Solid State Drives. In general, the SAS interface is more robust and
features better error detection and error processing. All of our highest performing SSDs, the enterprise
performance class drives, are SAS-based. But SATA SSDs may meet your performance requirements
applications.
Some enterprise mainstream SATA SSDs deliver surprisingly good performance in lower workload
environments. But SAS SSDs consistently outperform SATA SSDs for IOPS in higher workload
applications. This difference is more a function of the speed and robustness of the SAS processing core
on the SSD than of the SSD back-end architecture.
You should almost never use SATA SSDs behind SAS expanders. When you use an SAS expander, a
relatively large number of storage devices on the expander’s backside share the limited number of
dedicated SAS channels on the expander’s front side. SAS devices will only take control of a shared
channel when they have data to transfer. On the other hand, SATA drives, including SATA SSDs, take
control of a channel for the entire request/transfer cycle. They relinquish it only when they have
completed the entire operation. This major difference between the protocols significantly affects
performance when many SATA devices vie for access to the SAS channels.
HP IO Accelerators for ProLiant servers
HP IO Accelerators deliver the fastest solid state storage solution for HP ProLiant servers. Unlike SSDs,
which operate through the SATA or SAS interface of HP SmartArray controllers and Host Bus Adapters
(HBAs), IO accelerators provide solid state storage that is accessed directly across the PCI bus. IO
accelerators are ideally suited for environments requiring very high random read performance (greater
than 100,000 IOP/s) as well as significantly higher read and write throughput (up to 600 – 700
MB/s).
Conclusion
HP Solid State Drives are a storage solution ideally suited for certain types of server applications—
particularly those requiring superior random IOPS performance. You can use SSDs wherever you would
use a disk drive. But SSDs have some distinctly different performance characteristics. You should
consider them before deploying SSDs in a particular application environment. Additionally, SSDs have
a shorter lifespan, or endurance, than enterprise-level disk drives. Treat them as consumables to replace
when they reach the end of their usable lifespan. To help maximize an SSD’s lifespan, we have
developed HP SMARTSSD Wear Gauge technology for monitoring SSD usage and wear, and then
integrating this information into all HP management tools.