7065Admin_Configure.fm
Draft Document for Review August 30, 2007 12:59 am
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IBM System Storage DS3000: Introduction and Implementation Guide
Logical drives that have the following statuses cannot be used as a source logical drive or
target logical drive:
A logical drive that is reserved by the host cannot be selected as a source or target logical
drive.
A logical drive that is in a modification operation.
A logical drive that is the source logical drive or target logical drive in another VolumeCopy
with a status of Failed, In Progress, or Pending.
A logical drive with a status of Failed.
A logical drive with a status of Degraded.
8.5.5 VolumeCopy and performance considerations
During a VolumeCopy, data is read from the source logical drive and written to the target
logical drive in the same storage system. Because the VolumeCopy diverts controller
processes resources from I/O activity, it can affect I/O activity on the storage system. The
copy priority defines how much processing time is allocated for a VolumeCopy versus I/O
activity.
VolumeCopy priority rates
Several factors contribute to system performance, including I/O activity, logical drive RAID
level, logical drive configuration (number of drives in the array or cache parameters), and
logical drive type (FlashCopy logical drives can take more time to copy than standard logical
drives).
You can select the copy priority while you are creating a new VolumeCopy, or you can change
it later using the Copy Manager (described in 10.3.6, “Manage Logical Drive Copies” on
page 235). The following copy priority rates are available: Lowest, low, medium, high, and
highest.
8.5.6 VolumeCopy: Step-by-step
Here we will show how to setup VolumeCopy.
Check the status of the VolumeCopy Premium Feature
You need to check the VolumeCopy Premium Feature is licensed.
From the DS3000 Subsystem Management window, click the Tools tab and select
“View/Enable Premium features” The List Premium Features view opens and lists the
enabled premium features (Figure 8-69). Verify that “FlashCopy Logical Drives:” is
Enabled
. If
the FlashCopy feature is not enabled see 4.4.7, “(Optional) View and enable premium
Important: If you choose a base logical drive of a FlashCopy logical drive as your target
logical drive, you must disable all FlashCopy logical drives associated with the base logical
drive before you can select it as a target logical drive. Otherwise, the base logical drive
cannot be used as a target logical drive.
Note: The lowest priority rate supports I/O activity, but the VolumeCopy will take longer.
The highest priority rate supports the VolumeCopy, but I/O activity might be affected.
Remember, however, that VolumeCopy should always be used in conjunction with
FlashCopy.
