HP StorageWorks 6000 HP StorageWorks 6000-series Virtual Library System User G - Page 346

RAID A RAID volume consists of more than one drive, but appears to the operating system to be a single logical disk. RAID improves performance by disk striping, which involves partitioning each drive's storage space into units. By placing data on multiple disks, I/O operations can overlap in a balanced way, improving performance. RAID 1-level data storage Consists of at least two drives that use mirroring (100% duplication of the storage of data). There is no disk striping. Read performance is improved since either disk can be read at the same time. Write performance is the same as for single disk storage. RAID 5-level data storage Provides data disk striping at the byte level and also disk stripe error correction information. RAID 5 configurations can tolerate one drive failure. Even with a failed drive, the data in a RAID 5 volume can still be accessed normally. RAID 6-level data storage Provides data disk striping at the byte level and also disk stripe error correction information. RAID 6 configurations can tolerate two drive failures. Even with two failed drives, the data in a RAID 6 volume can still be accessed normally. RAID 6 read performance is similar to RAID 5, since all drives can service read operations, but the write performance is lower than that of RAID 5 because the parity data must be updated on multiple drives. redundancy In a redundant system, if you lose part of the system, it can continue to operate. For example, if you have two power supplies with one that takes over if the other one dies, that's redundancy. replication Similar to automigration. Data is written to virtual tape, and after the backups are complete, the data is written to another virtual tape, known as the replication target, over the LAN/WAN. secure sockets layer (SSL) certificate serial ATA (SATA) disk simple network management protocol (SNMP) A protocol designed to enable applications to transmit information back and forth securely. Applications that use this protocol inherently know how to give and receive encryption keys with other applications, as well as how to encrypt and decrypt data sent between the two. Some applications that are configured to run SSL include web browsers like Internet Explorer and Netscape, mail programs like GroupWise, Outlook, and Outlook Express, FTP (file transfer protocol) programs, etc. These programs are automatically able to receive SSL connections. To send an SSL connection, however, or to open a secure connection, your application must first have an encryption key assigned to it by a Certification Authority. Once it has a unique key of its own, you can establish a secure connection with every other application that can "speak" the SSL protocol. The evolution of the ATA (IDE) interface that changes the physical architecture from parallel to serial and from primary-secondary (master-slave) to point-to-point. Unlike parallel ATA interfaces that connect two drives; one configured as primary (master), the other as secondary (slave), each SATA drive is connected to its own interface. A widely used network monitoring and control protocol. Data is passed from SNMP agents, which are hardware and/or software processes reporting activity in each network device (hub, router, bridge, etc.) to the workstation console used to oversee the network. The agents return information contained in a MIB (Management Information Base), which is a data structure that defines what is obtainable from the device and what can be controlled (turned off, on, etc.). 346 Glossary