Solid state drive technology for ProLiant servers

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. Higher reliability SSDs must include controller designs

that manage NAND flash arrays while correcting problems caused by the following NAND error

modes:

 Read disturbs

 Program (write) disturbs

 Hot charge injection (bad cells can flip bits)

HP solid state drives for servers employ a variety of mechanisms that deliver a high level of reliability

required in server environments. They are:

 Longer-lasting SLC NAND technology

 Over-provisioning NAND memory to provide a longer lifecycle

 Wear leveling and block management

 Read and write algorithms that significantly reduce the frequency of NAND error modes

 End-to-end data path error detection

 Surprise power loss protection

With these technologies, HP solid state drives for servers achieve a level of reliability equivalent to or

slightly greater than current HP Enterprise disk drives for servers.

Perhaps more important for particular applications, HP server SSDs deliver this level of reliability

under conditions that are unsuitable for traditional disk drives, including environments of high-

temperatures and those of greater shocks and vibrations. Table 4 compares the operating envelope of

an HP server SSD with that of an HP small form factor SAS enterprise drive.

Table 4. Comparison of SSD and HD operating envelopes

HP 3 Gb/s SATA SSDs HP SFF 15K SAS HDD

Operating temperature 0° – 55° C 10°– 35° C

Operating

hock

1500 g

(.5 ms half sine wave)

30 g

(2 ms half sine wave)

Vibration

20 g peak

10 – 2000 Hz

1.5 g (RMS)

10 – 500 Hz

Power

onsumption

(active)*

Under 2 watts 8 – 9 watts

*Note: Power consumption will increase as performance levels improve on future devices