Specifications

Expansion Arrays
66 SnapServer Administrator Guide
multiple drive failures in a single RAID. See “RAID Groups” on page 54 for
information on how to avoid this.
Cautions
• Host server disk drives and expansion array disk drives are logically
interchangeable, but they are not physically interchangeable. That is, you
cannot physically take a disk drive from an expansion array and place it in a
host SnapServer. SnapServer disk drives contain GuardianOS-specific data
that is lacking on expansion array disk drives.
• Do not mix drives of different capacity in a RAID 1, 5, 6, or 10. The
redundancy schemes in these RAID types limit capacity usage in all member
drives to the capacity of the smallest member disk drive. For example, if a
RAID consists of one 160 GB disk drive and three 250 GB disk drives, the RAID
can use only 160 GB on each disk drive. In this case, the total RAID capacity is
approximately 640 GB (4 x 160) rather than the expected 910 GB (160 + [3 x
250]).
• Do not mix drives of different rotational speeds in the same column. See
“Adding New Disk Drives to Increase Capacity” on page 68 for illustrations of
supported and unsupported drive configurations.
Integrating Orphan Expansion Units
Expansion units that have been discovered by GuardianOS (e.g., are physically
connected to the SnapServer) but have not been integrated with the SnapServer are
listed in the Orphan Expansion Units table:
If you want to use the expansion unit with the SnapServer, click the check box next
to the orphan expansion unit you want to integrate, and click
OK.
Caution Before integrating an orphan expansion unit, be sure that it is compatible
with the SnapServer (e.g., data on the expansion unit is compatible with the
SnapServer configuration, Unicode settings are the same, etc.).
Property Description
Expansion Unit A description of the unit
Status The status of the unit (e.g., orphan)
Serial Number The expansion unit’s serial number
Origin The serial number of the server with which the expansion unit was
last incorporated