Binding Disk Modules Into Raid Groups - EMC CLARiiON DAE2P Hardware Reference Manual

Binding disk modules into RAID groups

Disk configuration rules and recommendations
After cabling the disk enclosure, use EMC Navisphere
software to bind the disks into RAID groups. Refer to the EMC
Navisphere Manager Administrator's Guide and your storage processor
configuration and planning guide for detailed information.
The following rules and recommendations apply to all CX-series and
CX3-series systems.
You cannot use any of the disks 000 through 004 (enclosure 0,
bus 0, disks 0-4) as a hot spare in a CX-series or CX3-series
system.
The hardware reserves several gigabytes on each of disks 000
through 004 for the cache vault and internal tables. To conserve
disk space, you should avoid binding any other disk into a RAID
group that includes any of these disks. Any disk you include in a
RAID group with a cache disk 000-004 is bound to match the
lower unreserved capacity, resulting in lost storage of several
gigabytes per disk.
Each disk in the RAID group should have the same capacity. All
disks in a Group are bound to match the smallest capacity disk,
and you could waste disk space. The first five drives (000-004)
should always be the same size.
You cannot mix drive types within a RAID group. ATA
(Advanced Technology Attachment), Fibre Channel, and Serial
ATA (SATA) disk drives cannot share a RAID group.
ATA drives require ATA hot spares. Hot spares for Fibre Channel
and SATA drives can be either type; we recommend SATA spares
for SATA drives and Fibre Channel spares for Fibre Channel
drives whenever possible.
If a storage system uses disks of different capacities and/or
speeds (for example, 146 GB and 73 GB, or 10K and 15K rpm)
within any enclosure, then EMC recommends that you place them
in a logical order, such as the following:
• Place drives with the highest capacity in the first (leftmost)
slots, followed by drives of lower capacities.
Binding disk modules into RAID groups
Installing a DAE2P/DAE3P
®
Manager
2-15