Dell PowerVault MD3000i Hardware Owner's Manual

Also see for PowerVault MD3000i: Getting started Tuning guide System installation guide User guide Information update

Contents

Dell PowerVault MD3000i Hardware Owner's Manual Manual pdf 39 page image

Using Your RAID Enclosure 39Disk Group DefragmentationDefragmenting consolidates the free capacity in the disk group into onecontiguous area. Defragmentation does not change the way in which the datais stored on the virtual disks.Disk Group Operations LimitThe maximum number of active, concurrent disk group processes percontroller is one. This limit is applied to the following disk group processes:virtual disk RAID level migration, segment size migration, virtual diskcapacity expansion, disk group expansion, and disk group defragmentation.If a redundant controller fails with an existing disk group process, the processon the failed controller is transferred to the peer controller. A transferredprocess is placed in a suspended state if there is an active disk group processon the peer controller. The suspended processes is resumed when the activeprocess on the peer controller completes or is stopped.NOTE: If you try to start a disk group process on a controller that does not have anexisting active process, the start attempt will fail if the first virtual disk in the diskgroup is owned by the other controller and there is an active process on the othercontroller.RAID Background Operations PriorityThe controller supports a common configurable priority for the followingRAID operations: background initialization, rebuild, copy back, virtual diskcapacity expansion, RAID level migration, segment size migration, disk groupexpansion, and disk group defragmentation.The priority of each of these operations can be changed to addressperformance requirements of the environment in which the operations are tobe executed.NOTE: Setting a high priority level will impact storage array performance. It is notadvisable to set priority levels at the maximum level. Priority should also beassessed in terms of impact to host server access and time to complete anoperation. For example, the longer a rebuild of a degraded virtual disk takes, thegreater the risk for potential secondary disk failure.