Assessments - 3, GPA: 4.3
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SCSI transfers eight or 16 bits in parallel and can operate in either asynchronous or synchronous modes. The synchronous transfer rate is up to 320 Mbytes/s (for Ultra320 SCSI). SCSI connections normally use single-ended drivers, as opposed to differential drivers. SCSI Channel MegaRAID controls the disk drives through SCSI-2 buses (channels) over which the system transfers data in either Fast and Wide or Ultra SCSI mode. Each adapter can control up to three SCSI channels. Internal and external disk drives can be mixed on channels 0 and 1, but not on channel 2. SCSI Drive State A SCSI physical drive can be in one of these states: . Online: Powered-on and operational. . Ready: Functioning normally, but not part of a configured logical drive and not designated as a hot spare. . Hot Spare: Powered-on stand-by disk drive, ready for use if an online disk fails. . Fail: Out of service, due to a fault occurring on the drive. . Rebuild: Currently being rebuilt with data from a failed drive. Copyright © 2002 by LSI Logic Corporation. All rights reserved. Service Provider The Service Provider (SP) is a program that resides in the desktop system or server and is responsible for all DMI activities. This layer collects management information from products (whether system hardware, peripherals, or software), stores that information in the DMI database, and passes it to management applications as requested. SNMP Simple Network Management Protocol. The most widely used protocol for communicating management information between the managed elements of a network and a network manager. SNMP focuses primarily on the network backbone. The Internet standard protocol that manages nodes on an Internet Protocol (IP) network. Spanning Array spanning by a logical drive combines storage space in two arrays of disk drives into a single, contiguous storage space in a logical drive. MegaRAID logical drives can span consecutively numbered arrays that each consist of the same number of disk drives. Array spanning promotes RAID levels 1 and 5 to RAID levels 10 and 50, respectively. See also Disk Spanning. Spare A disk drive available to back up the data of other drives. Stripe Size The amount of data contiguously written to each disk. You can specify stripe sizes of 4, 8, 16, 32, 64, and 128 Kbytes for each logical drive. For best performance, choose a stripe size equal to or smaller than the block size used by the host computer. Stripe Width The number of disk drives across which the data is striped. Striping Segmentation of logically sequential data, such as a single file, so that segments can be written to multiple physical devices in a round-robin fashion. This technique is useful if the processor can read or write data faster than a single disk can supply or accept it. While data is being transferred from the first disk, the second disk can locate the next segment. Data striping is used in some modern databases and in certain RAID devices. Terminator A resistor connected to a signal wire in a bus or network for impedance matching to prevent reflections—for example, a 50 ohm resistor connected across the end of an Ethernet cable. SCSI buses and some LocalTalk wiring schemes also require terminators. B-8 Glossary Copyright © 2002 by LSI Logic Corporation. All rights reserved. Ultra320 A subset of Ultra3 SCSI that allows a maximum throughput of 320 Mbytes/s, which is twice as fast as Wide Ultra2 SCSI. Ultra320 SCSI provides 320 Mbytes/s on a 16-bit connection. Virtual Sizing FlexRAID virtual sizing is used to create a logical drive up to 80 Gbytes. A maximum of 40 logical drives can be configured on a RAID controller, and RAID migration is possible for all logical drives except the fortieth. Because it is not possible to do migration on the last logical drive, the maximum space available for RAID migration is 560 Gbytes. Wide SCSI A variant on the SCSI-2 interface. Wide SCSI uses a 16-bit bus, double the width of the original SCSI-1. Wide SCSI devices cannot be connected to a SCSI-1 bus. Like Fast SCSI, Wide SCSI supports transfer rates up to 20 Mbytes/s. Copyright © 2002 by LSI Logic Corporation. All rights reserved. B-10 Glossary Copyright © 2002 by LSI Logic Corporation. All rights reserved. Index A Array B-1 Array Configuration Planner 5-14 Array management software B-1 Array performance features 4-3 Array spanning B-1 Assigning RAID levels 5-11 Asynchronous operations B-1 Audible Warnings A-1 Automatic failed drive detection and rebuild 4-4 B BIOS 4-6 BIOS Boot Error Messages 7-3 BIOS Configuration Utility 6-7 BIOS message 6-6 Bus data transfer rate 4-6 Bus type 4-6 Bus-based 2-11 Cache configuration 4-6 Cache I/O B-1 Cache Memory 4-7 Card size 4-6 Channel B-2 Cold swap B-2 Compatibility 4-9 Configuration on Disk 4-2 Configuration Strategies 5-9 Configuring Arrays 5-8 Configuring Logical Drives 5-12 Configuring SCSI physical drives 5-1 Consistency check 2-4, B-2 CPU 4-6 Creating hot spares 5-8 Creating logical drives 5-9 D Data redund...