HP LH4r HP Netserver LH 4 User Guide - Page 39

Chapter 6 Installing Mass Storage Devices Hot-Swap Mass Storage The Ultra2 SCSI hot-swap hard disk drives for mass storage come in two heights: the 1-inch low-profile drive and the 1.6-inch half-height drive. The Ultra2 drives are LVD (low voltage differential) drives, which allow the integration of the differential drivers and receivers into SCSI drive controllers. Ultra2 technology provides increased signal quality and ensures the same data integrity as the previous high voltage differential designs at a reduced cost. With the low voltage design, the SCSI bus cable can extend up to 12 meters. CAUTION Do not mix devices with high voltage differential (HVD) drivers and receivers and devices with SE, Ultra2 or multimode drivers and receivers on the same SCSI bus. I/O circuits used by devices with SE, Ultra2 or multimode drivers and receivers do not operate at HVD levels and should never be exposed to HVD environments. If you mix SCSI SE and SCSI Ultra2 devices, system performance will be adversely affected. For best performance, use only Ultra2 devices. Each Ultra2 disk drive module has two LED apertures: one for power status and one for activity status. Light pipes on the module transmit light to these apertures from LEDs on the inside rear of the hot-swap mass storage cage. The display meanings are described in Table 6-2. Table 6-2. Hard Disk Drive LED Indications Power Status LED Off: Disk not present, or not connected to the cage Green (solid): Disk present Activity Status LED Off: No disk activity Green (flashing): Accessing disk Green (Solid for more than one minute): Disk spinning up, or "hung" Amber (flashing): Disk failure predicted Red (solid): Disk failed 33