Users Guide
When a controller detects a congured physical disk, it ags the physical disk as foreign, and generates an alert indicating that a foreign
disk was detected.
CAUTION: Do not attempt disk migration during RLM or online capacity expansion (OCE). This causes loss of the virtual disk.
Migrating virtual disks
To migrate virtual disks from PERC H710, H710P, or H810 to PERC 9 series:
1 Turn o the system.
2 Ensure that all the latest rmware and drivers for the PERC H330, H730, H730P, H730P MX, or H830 card (available at Dell.com/
support/home) are installed on the destination system.
For more information, see Driver installation.
3 Move the physical disks from PERC H310, H710, H710P, or H810 card to the PERC 9 series.
4 Boot the system and import the foreign conguration that is detected. You can do one of the following:
• Press <F> to automatically import the foreign conguration.
• Enter the BIOS Conguration Utility and navigate to the Foreign Conguration View.
NOTE: For more information on accessing the BIOS Conguration Utility, see Entering the BIOS conguration
utility.
NOTE: For more information on Foreign Conguration View, see Foriegn Conguration
View.
5 Exit the BIOS Conguration Utility and reboot the system.
Virtual disk write cache policies
The write cache policy of a virtual disk determines how the controller handles writes to the virtual disk.
Table 3. Write cache policies
Feature Description
Write-Back The controller sends a data transfer completion signal to the host
when the controller cache has received all the data in a transaction.
The controller then writes the cached data to the storage device in
the background.
NOTE: The default cache setting for virtual disks is Write-
Back caching. Write-back caching is also supported for
single drive RAID 0 virtual disks.
Write-Through The controller sends a data transfer completion signal to the host
system when the disk subsystem has received all the data in a
transaction.
All RAID volumes are presented as Write-Through to the operating
system (Windows and Linux) independent of the actual write cache
policy of the virtual disk. The PERC cards manage the data in cache
independently of the operating system or any applications.
NOTE: Certain data patterns and congurations perform
better with a Write-Through cache policy.
Features 29