Virtual Disks - HP P2000 G3 MSA Technical White Paper

Technical white paper | HP P2000 G3 MSA
FC switch-attach configuration
When using a switch configuration, it is important to have at least one port connected from each switch to each controller
for redundancy. See Figure 6.
Figure 6. FC storage presentation during normal operation (high-availability, dual-controller, and switch attach with four hosts)
If controller B fails in this setup, the preferred path will shift to controller A and all volumes will be still accessible to both
servers as in Figure 6. Each switch has a redundant connection to all mapped volumes; therefore, the hosts connected to
the surviving controller maintain access to all volumes.

Virtual disks

A Vdisk is a group of disk drives configured with a RAID level. Each virtual disk can be configured with a different RAID level. A
virtual disk can contain SATA drives or SAS drives, but not both. The controller safeguards against improperly combining SAS
and SATA drives in a virtual disk. The system displays an error message if you choose drives that are not of the same type.
The HP P2000 G3 system can have a maximum of 16 virtual disks per controller in a dual controller system for a total of 32
virtual disks. In a single controller system, the maximum is 32 virtual disks.
For storage configurations with many drives, it is recommended to consider creating a few virtual disks each containing
many drives, as opposed to many virtual disks each containing a few drives. Having many virtual disks is not very efficient in
terms of drive usage when using RAID 3 or RAID 5. For example, one 12-drive RAID 5 virtual disk has one parity drive and 11
data drives, whereas four 3- drive RAID 5 virtual disks each have one parity drive (four total) and two data drives (only eight
total).
A virtual disk can be larger than 2 TB. This can increase the usable storage capacity of configurations by reducing the total
number of parity disks required when using parity-protected RAID levels. However, this differs from using volumes larger
than 2 TB, which requires specific operating system, HBA driver, and application-program support.
Note
The P2000 G3 can support a maximum volume size of 16 TB.
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