Dell PowerVault MD3820f - Manual (Page 85)

• The number of physical disks in the disk group
• The number of physical disk ports
• The processing power of the storage array RAID controller modules
If you want this operation to complete faster, you can change the modification priority to the highest
level, although this may decrease system I/O performance.
To change the segment size of a virtual disk:
1. In the AMW, select the Storage & Copy Services tab and select a virtual disk.
2. From the menu bar, select Storage → Virtual Disk → Change → Segment Size.
3. Select the required segment size.
A message prompts you to confirm the selected segment size.
4. Click Yes.
The segment size modification operation begins. The virtual disk icon in the Details pane shows an
Operation in Progress status while the operation is taking place.
NOTE: To view the progress or change the priority of the modification operation, select a virtual
disk in the disk group, and from the menu bar, select Storage → Virtual Disk → Change →
Modification Priority.
Changing The IO Type
You can specify the virtual disk I/O characteristics for the virtual disks that you are defining as part of the
storage array configuration. The expected I/O characteristics of the virtual disk is used by the system to
indicate an applicable default virtual disk segment size and dynamic cache read prefetch setting. See the
online help topics for information on the Automatic Configuration Wizard.
NOTE: The dynamic cache read prefetch setting can be changed later by selecting Storage →
Virtual Disk → Change → Cache Settings from the menu bar. You can change the segment size
later by selecting Storage → Virtual Disk → Change → Segment Size from the menu bar.
The I/O characteristic types shown below are only presented during the create virtual disk process.
When you choose one of the virtual disk I/O characteristics, the corresponding dynamic cache prefetch
setting and segment size that are typically well suited for expected I/O patterns are populated in the
Dynamic cache read prefetch field and the Segment size field.
To change the I/O type:
1. To enable read caching, select Enable read caching.
2. To enable dynamic cache read prefetch, select Enable dynamic cache read prefetch.
3. To enable write caching, select Enable write caching.
4. Select one of the following:
– Enable write caching with mirroring — Select this option to mirror cached data across two
redundant RAID controller modules that have the same cache size.
– Enable write caching without batteries — Select this option to permit write caching to continue
even if the RAID controller module batteries are discharged completely, not fully charged, or are
not present.
NOTE: Cache is automatically flushed if you disable Enable write caching.
5. Click OK.
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