Price and Performance Comparison for HDDs and HyperDrive4s and RAMSAN SSDs

For two good white papers on the advantages of SSDs over HDDs see...

www.texmemsys.com/files/f000173.pdf
www.texmemsys.com/files/f000174.pdf

Here is the comparison between a Western Digital Raptor Hard Disk, a HyperDrive4 and one 200 MB/s 50,000 IOPS 20 Microsecond latency port of what used to be the entry level RAMSAN SSD by Texas Memory Systems...

Capability WD740ADFD Raptor HyperDrive4 revision3 RAMSAN 120
Sustained Transfer Rate  77 MB/s 120 MB/s 200 MB/s
IOPS 100% random 512Byte files 270 44,000 50,000
Access Time 8.4 milliseconds 1 microsecond 20 microseconds
Power Fail Non volatile Passive Autobackup to HDD Active Autobackup to HDD 
Battery Backup Length Not needed 3 hours or 6 hours 30 mins? 
ECC Data Scrubbing  No No Yes
IBM Chipkill Technology  No No Yes
Memory Capacity  36GB, 72GB 0GB  - 16GB 8GB
Storage Medium  Rotating Glass Platter Registered ECC DDR Registered ECC DDR
Expandable Capacity No Yes No
Takes regular memory modules No Yes No
Form Factor 3.5" Drive 5.25" CD Drive size 1U Rackmount
Power Consumption 13 Watts 13-15 Watts 250 Watts
Weight 0.7Kg  1.15 Kg  or 1.3 Kg 20 Kg
Mechanical Failure? Yes No No
Price 110 1199 (0GB), 1799 (8GB), 2399 (16GB) 14,685

The 16GB HyperDrive4 is 160x faster in IOPS than the Raptor and 22x more expensive. The 8GB RAMSAN 120 is 185x faster in IOPS per port than the Raptor and 133x more expensive but only half the capacity of the HyperDrive4! 

Here is the comparison between 4 RAID0 Raptors 4 RAID0 HyperDrive4s and a RAMSAN 120 with both ports connected by a fibre switch. The RAID card used was a Silicon Image 3124-2 chip 4 port SATA RAID card with the latest SATARAID5 drivers from Silicon Image.

Capability 4x RAID0 WD740ADFD Raptor 4x RAID0 Sil3124-2 HyperDrive4 revision3 RAMSAN 120
Sustained Transfer Rate  230 MB/s 400 MB/s 400 MB/s
IOPS 100% random 512Byte files 500 104,000 100,000
Access Time 8.4 milliseconds 5-10 microseconds 20 microseconds
Power Fail Non volatile Passive Autobackup to HDD Active Autobackup to HDD 
Battery Backup Length Not needed 6 hours 30 mins? 
ECC Data Scrubbing  No No Yes
IBM Chipkill Technology  No No Yes
Memory Capacity  144GB, 288GB 0GB  - 64GB 8GB
Storage Medium  Rotating Glass Platter Registered ECC DDR Registered ECC DDR
Expandable Capacity No Yes No
Takes regular memory modules No Yes No
Form Factor 4x 3.5" Drives 4x 5.25" CD Drives 1U Rackmount
Power Consumption 52 Watts 52-60 Watts 250 Watts
Weight 2.8 Kg 5.2 Kg 20 Kg
Mechanical Failure Yes No No
Price 110 4999 (0GB), 5599 (8GB), 6199 (16GB), 7399 (32GB), 8599 (48GB), 9799 (64GB) 14,685

4 RAID0 HyperDrive4s outperform a RAMSAN 120 in speed and they cost half as much for twice the capacity!!

Here is the comparison between 32GB of HyperDrive4 storage in the form of 2 RAID0 HyperDrive4s and the 4 ported RAMSAN 325C, with all 4 ports connected by a fibre channel switch.

Capability 2x RAID0 Sil3124-2 HyperDrive4 revision3 fully populated RAMSAN 325C max capacity
Sustained Transfer Rate  218 MB/s 800 MB/s
IOPS 100% random 512Byte files 77,000 200,000
Access Time 5-10 microseconds 15-20 microseconds
Power Fail Passive Autobackup to HDD Active Autobackup to HDD 
Battery Backup Length 3 or 6 hours 30 mins? 
ECC Data Scrubbing  No Yes
IBM Chipkill Technology  No Yes
Memory Capacity  32GB 32GB
Storage Medium  Registered ECC DDR Registered ECC DDR
Expandable Capacity No No
Takes regular memory modules Yes No
Form Factor 2x 5.25" CD Drives 3U Rackmount
Power Consumption 26-30 Watts 250 Watts
Weight 2.3 or 2.6 Kg 32 Kg
Mechanical Failure No No
Price 4,800 48,000

The RAMSAN is 3x faster in IOPS although not much faster per port (50,000 IOPS) and it is 10x more expensive. If you need 32GB of lightening fast storage, at least an order of magnitude faster in IOPS than hard disk arrays can manage, then 2 RAID0 HyperDrive4s are plainly the Value Solution.

Copyright HyperOs Systems London March 2007.