Not all SSDs technology is the same. In this review we are highlighting the differences between the different HPE branded SSD drives. HPE uses several different technologies and design requirements so that our server SSDs can meet the reliability and endurance requirements of server storage.
Wear leveling and over-provisioning
HPE SSDs incorporate wear leveling and over-provisioning to meet the endurance requirements for enterprise environments. These technologies increase the lifespan of an SSD drive in an enterprise environment.
Over-provisioning distributes the total number of writes and erases across a larger number of blocks and pages over time. On Enterprise SSDs, the over-provisioning can reach as high as 25 percent above the stated storage capacity.
Wear leveling uses sophisticated algorithms that re-map logical SCSI blocks receiving frequent writes to different physical pages. It evenly distributes erasures and rewrites across the medium to maximize endurance. A pointer array on the SSD controller contains the logical-to-physical map. SSDs can recover or rebuild the map quickly after a power loss.
Power loss protection HPE
ProLiant SSDs have power loss protection. It ensures that if the drive loses power (including hot plug removal), it can be ready in a short time. Power loss protection also ensures that user data in write cache writes to the drive. HPE SSDs can sustain a power loss without requiring the lengthy metadata rebuild process required for SSDs without power-loss protection.
Value, mainstream, and performance SSDs
HPE supports three SSD Enterprise classes (Table Below) to meet the requirements of different application environments: value, mainstream, and performance SSDs. They all deliver I/O performance comparable to Enterprise spinning media drives. SSDs differ from spinning media drives primarily by the read/write workload levels they can support and their expected service life.
- Enterprise value SSDs provide relatively large storage capacities at low costs, but they do not have the endurance of the mainstream or performance SSDs.
- Creativity mainstream SSDs have smaller capacities but greater endurance than value SSDs.
- Enterprise performance SSDs from HPE have similar capacities to mainstream SSDs but have even greater endurance.
All SSDs can operate in environments unsuitable for spinning media drives:
- Environments subject to high shock and vibration, up to 1000G
- Environments subject to higher operating temperatures, depending on the SSD
Based on published workloads, we expect HPE SSDs to last the typical service life for a new server. The lifespan of NAND memory in SSDs is determined by the number of write/erase cycles it experiences. SSD endurance is different from disk drive endurance. A server SSD reaching the end of its service life is likely to start failing once it exceeds the NAND endurance limit. A SAS disk drive may continue operating for several years beyond its stated service life. An SSD removed from a system without power may not be readable after a short time, but most spinning media drives will retain their data for a decade or more. SSDs are unsuitable for use as archival storage because they do not have great data retention characteristics.
Second generation HPE SSDs perform significantly better than the first generation from 2008. Table 6 shows that second generation midline SSD performance is comparable to Enterprise SAS drive performance. SSDs excel at random read operations, where performance can be over 100 times better than that of spinning media drives.
Cause of the advancements in storage technology, you now can decide from a broad spectrum of drives, each with unique performance and reliability characteristics. When considering which technology to select for your implementation, you need to contemplate these requirements
- Capacity needed
- Expected I/O load
- Desired lifecycle
- Required reliability
HPE has industry-leading drive technologies to handle all of your storage requirements. All of their storage products are rigorously tested and certified for their targeted applications.
By: Vam Gangam – Lanworks Head Office, Mississauga (Toronto), Ontario
Lanworks – Over 30 years of experience in providing Personalized IT for Your Business