HP 3000 Enterprise Virtual Array - Manual (Page 38)

Adding disk drives to the storage system
As your storage requirements grow, you may be adding disk drives to your storage system. Adding new
disk drives is the easiest way to increase the storage capacity of the storage system. Disk drives can be
added online without impacting storage system operation.
Guidelines for adding disk drives
When adding new disk drives to the storage system, you should ensure that the disk drives are installed
in the correct positions to maintain availability. The disk drives should be distributed across the disk
enclosures to protect against the failure of a single disk enclosure.
Use the following guidelines when adding disk drives to your storage system:
• Install high performance and FATA disk drives in separate groups. These different drive types must
be in separate disk groups. You may also want to consider separating different drive capacities
and spindle speeds into different groups.
• The disk drives should be distributed evenly across the disk enclosures. The number of disks of
a given type in each enclosure should not differ by more than one. For example, no enclosure
should have two disks until all the other enclosures have at least one.
• Disk drives should be installed in vertical columns within the disk enclosures. Add drives vertically
in multiples of eight, completely filling columns if possible. Disk groups are more robust if filled
with the same number of disk drives in each enclosure. See Figure 6 for an example.
NOTE:
When adding multiple disk drives, add a disk and wait for its activity indicator (1) to stop flashing
(up to 90 seconds) before installing the next disk (see Figure 5 ). This procedure must be followed to
avoid unexpected EVA system behavior.
Figure 5 Disk drive activity indicator
Creating disk groups
The new disks you add will typically be used to create new disk groups. Although you cannot select
which disks will be part of a disk group, you can control this by building the disk groups sequentially.
Add the disk drives required for the first disk group, and then create a disk group using these disk drives.
Now add the disk drives for the second disk group, and then create that disk group. This process gives
you control over which disk drives are included in each disk group. Figure 6 shows the sequential
building of vertical disk groups.
38 Enterprise Virtual Array operation