Disk Options and Comparisons
We have 3 disk options that conform with the low power requirement (< 2-3 Watts?):
To compare options amongst these drives, we need common parameters that give us a decent and standard metric. Some parameters are:
- Power Consumption (Idle and Peak)
- Read/Write Speed (Data Transfer Rate)
- Sequential Data
- Random Data
- Cost per Gigabyte
- I/O Interface Support and Bottlenecks
- PCIe
- USB 2.0/3.0
- SD/MMC
RAID0
RAID0 gives the option to provide better read/write performance. Although it is not the best option for reliability.
The SSD used is OCZ Vertex2 120GB (Measured 230 MB/s write and 275 MB/s read throughput on Atom D510MO motherboard)
RAID0 was built both on Core 2 and Atom D510.
Core 2
2 disks RAID0 was installed on Core2 and achieved measured 469 MB/s write throughput. It is the value close to double of single disk performance.
Atom D510
- SATA was treated as IDE
However 2 disks RAID0 was installed on Atom D510 but only achieved 295 MB/s (hdparm) write throughput and 304 MB/s read throughput. The results shows far less than expected double performance.
Atom D510 uses DMI bus which has theoretical limit 10Gb/s. It needs at least four SSDs to saturate and is not the bottleneck.
Interesting result through testing read throughput from reading from two disks at them same time, shows a rough read throughput over 450 MB/s. This test indicate that RAID0 throughput was limited by internal software bottleneck.
- SATA was treated as Advanced Host Controller Interface (AHCI)
Similar as results of IDE setting
