Solid state drive technology for ProLiant servers

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Solid state storage technology for ProLiant

servers

edition

echnology brief

Introduction......................................................................................................................................... 2

Flash memory technology ..................................................................................................................... 2

Single-level and multi-level cell NAND flash......................................................................................... 2

NAND architecture .......................................................................................................................... 3

Design of solid state drives with flash memory......................................................................................... 4

Wear leveling for increased SSD endurance ....................................................................................... 5

Over-provisioning NAND.................................................................................................................. 5

HP solid state drives for ProLiant servers ................................................................................................. 5

Performance of HP server SSDs.......................................................................................................... 5

HP server SSD reliability ................................................................................................................... 6

Server SSDs for different needs – value, mainstream, and performance .................................................. 7

I/O accelerators – the new kid on the storage “block”............................................................................. 7

I/O accelerator architecture .............................................................................................................. 8

HP PCIe IO Accelerator models ......................................................................................................... 9

HP PCIe IO Accelerator performance.................................................................................................. 9

Summary ............................................................................................................................................ 9

For more information.......................................................................................................................... 10

Call to action .................................................................................................................................... 10

Summary of content (10 pages)

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Solid state storage technology for ProLiant servers 2nd edition Technology brief Introduction......................................................................................................................................... 2 Flash memory technology ..................................................................................................................... 2 Single-level and multi-level cell NAND flash.........................................................................................
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Introduction HP is now delivering solid state storage devices based on flash memory in addition to traditional disk drives based on spinning magnetic media. Solid state drives (SSDs) are the most familiar of these new devices, since they are plug-compatible with disk drives and used with traditional SATA/SAS disk controllers. But we are also introducing new types of flash-based storage devices for ProLiant servers that will significantly improve performance for certain types of applications.
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times greater than that of MLC flash. SLC NAND’s higher performance and better reliability are preferred for designing solid state drives that meet the requirements of unconstrained workload environments. But there will also be MLC-based SSDs for use in read intensive application environments with limited write requirements. NAND architecture NAND flash memory arrays are organized into pages and blocks. A page is the smallest unit.
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Table 2. SLC NAND flash operations Operation Minimum execution time Random page read 25 microseconds Page program (write) 200 microseconds Block erase 1500 microseconds As Table 2 shows, writing to NAND flash is a slower operation than reading from it. A page program operation is eight times slower than a random page read. A block erase operation, executed less frequently, is seven times slower than page program operation.
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Wear leveling for increased SSD endurance Wear leveling is one of the design techniques engineers use to increase the endurance of NANDbased SSDs. Since NAND-based SLC flash supports only 100,000 lifetime write/erase cycles, the SSD needs to not erase and rewrite NAND blocks any more than is necessary. But application usage may require frequent updates or rewrites of some logical SCSI blocks in a SAS/SATA device.
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Table 3. Comparison of typical SSD and HDD performance (actual performance numbers may vary) HP 3 Gb/s SATA SSD HP SFF 15K SAS HDD Random reads (4 KB) 18,000 IOPs 340 IOPs Random writes (4 KB) 3000 IOPs 285 IOPs Sequential read throughput (64 KB) 220 MB/s 105 MB/s Sequential write throughput (64 KB) 120 MB/s 150 MB/s HP server SSD reliability Reliability is an important criterion when selecting a storage device for use in a server. But not all SSDs are more reliable than hard disk drives.
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Server SSDs for different needs – value, mainstream, and performance Our current 3 Gb/s SATA solid state drives are just the first building blocks for an HP family of SSDs designed to meet a variety of workload, capacity, and performance requirements. All HP SSDs are Enterprise-class devices because they deliver I/O performance -- particularly read performance -- that is as good as or better than Enterprise-class disk drives.
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controller and its SAS or SATA channels. An I/O Accelerator is its own controller and storage device, requiring its own specialized driver and delivering block I/O directly across the PCIe bus. As we will see, this gives it some distinct performance advantages for use in particular application environments.
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SAS channels and no Smart Array controller front end, the only physical restraint to throughput is the bandwidth of the PCIe bus. HP PCIe IO Accelerator models HP delivers the PCIe IO Accelerator in two different product configurations – the ioDrive and the ioDrive Duo. The ioDrive is a low-profile PCIe x4 device available with either 160 GB of SLC NAND memory or 320 GB of MLC NAND. The ioDrive Duo, at the hardware level, consists of two separate NAND storage devices.
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For more information For additional information, refer to the resources listed below. Resource description Web address HP Solid State Storage web page www.hp.com/go/solidstate HP ProLiant drives (including solid state drives) www.hp.com/products/harddiskdrives HP PCIe IO Accelerator web page http://h18004.www1.hp.com/products/servers/proliantstorage /solid-state/index.html?jumpid=reg_R1002_USEN Comparison of SSD, ioDrives, and SAS rotational drives using TPC-H Benchmark http://h20195.www2.hp.