Dell EMC PowerVault MD 34XX/38XX Series Storage Arrays Administrator's Guide

When you create a thin virtual disk from free capacity in an existing disk pool, you can manually set disk attributes or allow MD Storage Manager to assign default attributes. The following manual attributes are available:

• Preferred Capacity — Sets the initial physical capacity of the virtual disk (MB, GB or TB). Preferred capacity in a disk pool is allocated in 4 GB increments. If you specify a capacity amount that is not a multiple of 4 GB, MD Storage Manager assigns a 4 GB multiple and assigns the remainder as unused. If space exists that is not a 4 GB multiple, you can use it to increase the size of the thin virtual disk. To increase the size of the thin virtual disk, select Storage > Virtual Disk > Increase Capacity.
• Repository Expansion Policy — Select either Automatic or Manual to indicate whether MD Storage Manager must automatically expand physical capacity thresholds. If you select Automatic, enter a Maximum Expansion Capacity value that triggers automatic capacity expansion. The MD Storage Manager expands the preferred capacity in increments of 4 GB until it reaches the specified capacity. If you select Manual, automatic expansion does not occur and an alert is displayed when the Warning Threshold value percentage is reached.
• Warning Threshold — When consumed capacity reaches the specified percentage, MD Storage Manager sends an E-mail or SNMP alert.