Dell PowerEdge R740 EMC PowerEdge RAID Controller S140 Users Guide - Page 17

Virtual disk migration, Expanding virtual disk capacity

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Table 6. Read, Write, and Cache Policy for the PERC S140 (continued) Category Supported by S140 controller No Read Ahead/Write Back Yes Read Ahead/Write Through Yes No Read Ahead/Write Through Yes NOTE: The current default for Write-Cache mode enablement is Write Through, No Read Ahead (WT, NRA). To enable Write Back (WB), a UPS is recommended. NOTE: For more information about the physical disk write cache policy behavior, see Troubleshooting your system on page 42 Virtual disk migration The PERC S140 supports automatic virtual disk migration from one PERC S140 to another. CAUTION: The virtual disk is lost if you perform a virtual disk migration during an Online Capacity Expansion (OCE)/ Reconfigure. NOTE: Back up the virtual disk data before migrating virtual disks. NOTE: Ensure that all physical disks that are part of the virtual disk are migrated. Virtual disks in optimal and degraded states are automatically migrated. A virtual disk in an offline state should not be migrated. NOTE: A bootable virtual disk cannot be migrated between dissimilar system models. NOTE: When you migrate virtual disks, ensure that you verify that the number of virtual disks does not exceed 10. Migrating a virtual disk 1. Turn off the system that contains the source controller. 2. Turn off the target system if the system does not support hot swap of physical disks. 3. Move the appropriate physical disks from the source controller to the target controller in the target system. Physical disks do not have to be inserted into the same slots in the target system. 4. If the target system was turned off, turn on the system. CAUTION: The BIOS Configuration Utility pauses, and prompts for action, for the degraded virtual disk(s), if the "pause if degraded" option is enabled in the BIOS Configuration Utility. CAUTION: After the migration occurs, ensure that all of the physical disks have been migrated and are present in the appropriate virtual disks. Expanding virtual disk capacity The capacity of a virtual disk can be expanded online by using the Online Capacity Expansion/Reconfigure (OCE/Reconfigure). OCE/ Reconfigure is a process that allows you to add storage capacity to an existing virtual disk. In most cases additional storage capacity can be added without taking the system offline. NOTE: If an additional physical disk is required and the system does not support hot-swapping, the system must be turned off. OCE/Reconfigure enables you to increase the total storage capacity of a virtual disk by integrating unused storage with the virtual disk. Data can be accessed while the physical disks are added (if a system has hot-swap capability) and while data on the virtual disk is being redistributed. For volume, RAID 1, and RAID 10, OCE/Reconfigure expands the virtual disk by using the available space of the physical disks, which have been members of the virtual disk. For RAID 0 and RAID 5, additional capacity can be attained by adding physical disks to the virtual disk. Virtual Disks 17

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Table 6. Read, Write, and Cache Policy for the PERC S140
(continued)
Category
Supported by S140 controller
No Read Ahead/Write Back
Yes
Read Ahead/Write Through
Yes
No Read Ahead/Write Through
Yes
NOTE:
The current default for Write-Cache mode enablement is Write Through, No Read Ahead (WT, NRA). To enable
Write Back (WB), a UPS is recommended.
NOTE:
For more information about the physical disk write cache policy behavior, see
Troubleshooting your system
on
page 42
Virtual disk migration
The PERC S140 supports automatic virtual disk migration from one PERC S140 to another.
CAUTION:
The virtual disk is lost if you perform a virtual disk migration during an Online Capacity Expansion (OCE)/
Reconfigure.
NOTE:
Back up the virtual disk data before migrating virtual disks.
NOTE:
Ensure that all physical disks that are part of the virtual disk are migrated. Virtual disks in optimal and degraded
states are automatically migrated. A virtual disk in an offline state should not be migrated.
NOTE:
A bootable virtual disk cannot be migrated between dissimilar system models.
NOTE:
When you migrate virtual disks, ensure that you verify that the number of virtual disks does not exceed 10.
Migrating a virtual disk
1.
Turn off the system that contains the source controller.
2.
Turn off the target system if the system does not support hot swap of physical disks.
3.
Move the appropriate physical disks from the source controller to the target controller in the target system.
Physical disks do not have to be inserted into the same slots in the target system.
4.
If the target system was turned off, turn on the system.
CAUTION:
The BIOS Configuration Utility pauses, and prompts for action, for the degraded virtual disk(s), if the "pause
if degraded" option is enabled in the BIOS Configuration Utility.
CAUTION:
After the migration occurs, ensure that all of the physical disks have been migrated and are present in the
appropriate virtual disks.
Expanding virtual disk capacity
The capacity of a virtual disk can be expanded online by using the Online Capacity Expansion/Reconfigure (OCE/Reconfigure). OCE/
Reconfigure is a process that allows you to add storage capacity to an existing virtual disk. In most cases additional storage capacity can
be added without taking the system offline.
NOTE:
If an additional physical disk is required and the system does not support hot-swapping, the system must be
turned off.
OCE/Reconfigure enables you to increase the total storage capacity of a virtual disk by integrating unused storage with the virtual disk.
Data can be accessed while the physical disks are added (if a system has hot-swap capability) and while data on the virtual disk is being
redistributed.
For volume, RAID 1, and RAID 10, OCE/Reconfigure expands the virtual disk by using the available space of the physical disks, which have
been members of the virtual disk. For RAID 0 and RAID 5, additional capacity can be attained by adding physical disks to the virtual disk.
Virtual Disks
17