Introduction to Shared PERC

High-level Shared PERC 8 specifications

Shared PERC features

Documentation

Introduction to Shared PERC 

The Shared PERC 8 cards are available in the following form factors:

  • Shared PERC 8 internal card – manages the internal storage on the VRTX enclosure. The Shared PERC 8 Internal cards are connected on the PERC slots labeled PERC1 and PERC2.
  • Shared PERC 8 external card – extends storage capacity by allowing server modules to access up to two external JBODs. The Shared PERC 8 External cards are connected through PCIe slots 5 and 6 on the VRTX system. Shared PERC 8 External card supports MD1200 or MD1220 JBOD.

The Shared PERC 8 Internal and External cards are two separate SAS domains. The PowerEdge VRTX system is available in the following configurations for both internal and external cards:

Single Non-Fault Shared PERC 8 Card Configuration: In this configuration, the controllers do not mirror their cache. The default cache policy for virtual disks created in this configuration is write-back. In this mode, the write completion information is returned to the host after the data is written to the Shared PERC 8 controller’s cache.

Dual Fault Tolerant Shared PERC 8 Card Configuration: In this configuration, there are two Shared PERC 8 cards configured in an active-passive cluster. Both controllers can access the same storage subsystem. However, only the active controller provides the data access. If one of the Shared PERC 8 cards fails, the other Shared PERC 8 card takes control in a seamless transition. The default cache policy for virtual disks created in this configuration is write-back.

NOTE: For Shared PERC 8 External controllers, the Fault Tolerance option must be set by the user and the required cabling topology must be used.

Dual Non-Fault Tolerant Shared PERC 8 External Cards Configuration: In this configuration, the PowerEdge VRTX system contains two Shared PERC 8 External cards where both are cabled to separate JBODs creating separate SAS domains. If one Shared PERC 8 External card fails, access to the storage 8 subsystem attached to that card is lost. This configuration option is not available for Shared PERC 8 Internal cards. However, migration of disks from Shared PERC 8 internal to external cards is possible as long as they have the same firmware.

Note: This configuration is only available for external cards.

The Shared PERC 8 Internal card controls the internal storage enclosure on the VRTX chassis. 

High-level Shared PERC 8 specifications

Supported drives

Dell-qualified SAS hard drives and SAS solid-state drives (SSDs). Mixing disks of different speeds (7,200 rpm, 10,000 rpm, or 15,000 rpm) and bandwidth (6 Gbps or higher) while maintaining the same drive type (SAS) and technology (HDD or SSD) is supported. However, this may affect data transfer performance

RAID levels

0, 1, 5, 6, 10, 50, and 60

NOTE: Non-RAID drives are not supported.

Virtual functions

Four virtual functions to support up to four host servers

Management application

Dell Chassis Management Controller (CMC). NOTE: Option ROM (OP-ROM) is not supported. Booting from a shared storage is not supported. You can only boot from the storage on the server module.

Enclosure per external domain

2

Processor

Dell Adapter SAS RAID-on-Chip, 8 Port with LSI 2208 chipset

Battery backup unit

Yes

Nonvolatile cache

Yes

Cache memory

1 GB DDR3, 1333 MHz

Cache policies

Write Back, Forced Write-Back, Write Through, Adaptive ReadAhead, No Read-Ahead, and Read Ahead

Maximum number of spans per disk group

8

Maximum number of virtual disks per disk group

16

Maximum number of virtual disks

64

Hardware XOR engine

Yes

PCIe hot plug of controller

PCIe Hot Add only supported with Shared PERC 8 External card

Multipath support

Required for systems with Fault Tolerant Shared PERC 8 card configuration.

Controller failover

Available only for systems with Fault Tolerant Shared PERC 8 card configuration.

Shared PERC Features

The Dell PowerEdge RAID Controller (PERC) line of storage controllers offers the following high level features: 

Documentation