HP A3550A User Guide - Page 178

Grid Manager Group to bind Restrictions and recommendations Any group RAID-5 group RAID-1 mirrored pair RAID-1/0 group Global hot spare Only unbound (UNB) disk modules can be bound. If an attempt is made to bind a module that is binding (BIN), Grid Manager displays an error message. All disk modules in a group must be of the same type and same capacity to use the modules' storage space fully. The capacity of a disk module can be determined in Grid Manager by selecting that module in the Presentation screen and pressing RETURN. A minimum of three and a maximum of 16 disk modules must be bound. However, for more efficient use of disk space, it is recommended that five disk modules be bound. Note: MPE/iX has a 16-Gbyte limit for volumes and a 4-Gbyte limit for Ldevs. An even number of disk modules -- from a minimum of two to a maximum of 16 - must be bound. The disk modules can be selected in any order and each disk module in a pair should be on a separate bus. The maximum number of disks is 16 for model 20. A minimum of four disk modules and an even number of modules must be bound. Grid Manager pairs modules into mirrored images in the order that they are selected. The first and second modules selected become a pair of mirrored images; the third and fourth modules selected become another mirrored pair; and so on. The first module selected in each pair is the primary image; the second module is the secondary image. Used in RAID-5, RAID-1, and RAID-1/0. The capacity of a disk module bound as a hot spare must be at least as great as the capacity of the largest disk module that it might replace. On a model 20, the disk modules in slots A0, B0, C0 or A3 cannot be bound as a hot spare because they are the database drives that contain the SP microcode. In addition to the above, the disk drives in slots DO and EO (model 20) cannot be bound as hot spares if cache is installed because they are cache vault drives. Hot spares should never be assigned LUN number 0. Hot spares are assigned a LUN number but are not recognized as an addressable LUN by the host. 6-39