A REFERENCE GUIDE FOR OPTIMIZING DELL™ MD1000 SAS SOLUTIONS VER A00
PAGE 15 5/06/2005
5. PERC 5/E Controller - Detailed Features
PERC 5/E is the RAID controller used to connect the PowerVault MD1000 storage enclosure with
PowerEdge servers. It supports 3 Gbps Serial Attached SCSI (SAS) as the storage interconnect
technology and PCI -E as the host-based interconnect technology. PERC 5/E controller supports
RAID levels 0, 1, 5, 10 and 50.
Considerations when implementing a RAID Solution
The selection of a RAID solution in any environment is governed by several aspects including
controller and capacity requirements. Each of these factors is discussed in detail in the following
sections.
Controller Features
The Server Administrator is the recommended application for configuring and managing the
PowerVault MD1000 storage enclosure. Apart from the Server Administrator software, the BIOS
configuration utility (<CTRL> <R>) may be used to perform pre-OS configuration and fault
recovery. Some of the key features of the PERC 5/E controller are listed here:
• Virtual Disk Initialization
PERC 5/E controller is capable of performing initialization on the virtual disk(s) by either
writing 0’s to a portion of the physical disk (fast initialization) or to the entire physical disk
(full initialization). Full initialization guarantees that any legacy data is cleared and all
sectors are healthy.
• Background Patrol Read
Background Patrol Read is an automatically scheduled background task that scans and
resolves possible physical disk errors that may lead to physical disk failure and result in
data integrity issues. Dell recommends implementing Background Patrol Read in all the
configurations.
• Consistency Check/Background Initialization (BGI)
Consistency checks / BGI are performed by PERC 5/E controller to verify that all stripes in
a redundant virtual disk are consistent and to automatically correct stripes where
inconsistencies are found. BGI is a consistency check that automatically runs on all
redundant arrays. Depending on workload, Dell recommends that consistency checks are
run manually on virtual disks at least once every month to ensure data integrity. Running a
consistency check is complement to running Patrol Read and both should be used.
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