Disk Subsystems
For processing outside-of-memory datasets, Vector needs, above all, a high performance sequential read disk subsystem. This can be achieved using multiple magnetic disks in RAID, using any of these technologies:
• SCSI
• SAS
• SATA
Because random lookups are not as important in a data warehousing context, using SAS hardware tends to be the cost effective option.
Solid State Drives (SSD), which typically use SATA, are more expensive per gigabyte, but high-end models deliver more than 2.5 times the sequential throughput of a single magnetic disk. They also come in a 2.5-inch form factor, allowing higher "bandwidth density".
Be sure to balance SSDs with enough disk controllers: at least one controller is needed per four drives. Because Vector uses advanced differential techniques for handling updates efficiently, the amount of write operations is significantly reduced, so using cost-effective "MLC" memory SSDs is an option.