3PAR InForm® OS 2.3.1 Concepts Guide (320-200112 Rev B, February 2010)

8.3
RAID Types
InForm OS Version 2.3.1 3PAR InForm OS Concepts Guide
system during the initial installation and setup of the storage server. Each controller node
in the system has a 20 GB logging LD.
■ preserved data logical disks are RAID 10 logical disks used to hold preserved data. Preserved
data logical disks are created by the system during the initial installation and setup of the
storage system. The size of the preserved data LD is based on the amount of data cache in
the system.
When multiple disk failures during write operations leave data suspended in cache
memory, the system temporarily preserves this data by writing it to a preserved data logical
disk. By doing so, the system clears the data cache and prevents it from locking up and
leading to wider system failures. When the destination logical disks become available
again, the system automatically writes the preserved data from the preserved data logical
disks to the destination logical disks.
■ Administration volume logical disks provide storage space for the admin volume, a single
volume created on each system during installation. The admin volume is used to store
system administrative data such as the system event log.
8.4 RAID Types
The 3PAR storage system supports the following RAID types:
■ RAID 0
■ RAID 10 (RAID 1)
■ RAID 50 (RAID 5)
■ RAID Multi-parity (MP)