Users Guide

NOTE: If you are moving an entire just a bunch of disks (JBOD) enclosure, make sure to turn o the JBOD before cabling to the
new controller.
Using physical disk roaming
Perform the following steps to use disk roaming:
1 Turn o the power to the system, physical disks, enclosures, and system components.
2 Disconnect power cables from the system.
3 Move the physical disks to the required positions on the backplane or the enclosure.
4 Perform a safety check. Make sure the physical disks are inserted properly.
5 Turn on the system.
The controller detects the RAID conguration from the conguration data on the physical disks.
FastPath
The Shared PERC 8 card supports FastPath feature, which improves application performance by delivering high I/O per second (IOPS).
Under specic conditions with FastPath, the I/O bypasses the controller cache and is committed directly to the physical disk from the host
memory or directly from the physical disk. All simple nonspanned virtual disks congured with Write-Through write-cache policy and No
Read-Ahead read-cache policy can utilize FastPath.
Workloads on SSD volumes provide the most performance improvement with FastPath.
The following conditions support FastPath:
• Random workloads with small blocks.
• I/O block sizes smaller than virtual disk’s stripe size.
• Sequential read workloads on unspanned RAID volumes (RAID 0, RAID 1, RAID 5, and RAID 6).
• Sequential read and write workloads on RAID 0 virtual disks.
The following conditions do not support FastPath:
• Virtual disks running background operations such as rebuild, initialization, and so on.
• Spanned RAID volumes like RAID 10, RAID 50, and RAID 60.
Virtual disk migration
The Shared PERC 8 card supports migration of virtual disks from one controller to another without taking the target controller oine. The
controller can import RAID virtual disks in optimal, degraded, or partially degraded states. Migration of virtual disks from Shared PERC
internal to Shared PERC external is supported.
The Shared PERC 8 card does not support virtual disk migration:
• Where the virtual disk is in a failed state.
• When the virtual disk is removed while the source system is turned on.
• From any other PERC cards such as PERC H310, H700, H710, H800, and H810.
The Shared PERC 8 card supports virtual disk migration:
• From a similar Shared PERC 8 card.
• From the Single Shared PERC 8 card conguration to the Fault Tolerant Shared PERC 8 card conguration, but not from a newer
rmware version to an older rmware version system.
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Shared PERC 8 card features