User guide

Introduction 1-7
Features
The advanced features supported by the RA4000 Controller are:
■ Support for RAID 0, 1, 4, and 5 fault-tolerance options
■ Fibre Channel support for connection to the server
■ Support for Compaq Hot Plug Ultra2 Disk Drives at Wide-Ultra SCSI-3
speeds.
■ Online Capacity Expansion (Microsoft Windows NT and Novell
NetWare only)
■ Online Volume Extension (Windows NT requires reboot)
■ Online Stripe Size Migration
■ Online RAID Migration
■ Removable RA4000 Controller Cache
■ Battery-backed 64-MB Cache with ECC memory
■ Controller board containing a 16-MB Read Cache
■ Performance monitoring through Compaq Insight Manager
■ Automatic performance tuning
■ Pre-failure notification on hard disk drives
■ Array Configuration Utility (ACU)
■ Read-ahead caching
■ Tagged-command queuing
■ Multiple logical drives per RA4100
■ Array Diagnostics Utility (ADU)
Hard Drive Arrays
Drive array technology distributes data across a series of hard drives to unite
these physical drives into one or more higher performance logical drives.
Distributing the data makes it possible to access it concurrently from multiple
drives in the array, yielding faster I/O rates than nonarrayed drives. Each
logical drive in the array can be set to a different fault-tolerant configuration.
The RA4000 Controller manages the drive array independent of the host
processor. For more information on storage expansion, see Appendix E, “Hard
Drive Arrays.”