Planning: MD3200i Series Storage Array Terms and Concepts 45Virtual Disk Operations LimitThe maximum number of active, concurrent virtual disk processes per RAIDcontroller module installed in the storage array is four. This limit is applied tothe following virtual disk processes:• Background initialization• Foreground initialization• Consistency check• Rebuild• Copy backIf a redundant RAID controller module fails with existing virtual diskprocesses, the processes on the failed controller are transferred to the peercontroller. A transferred process is placed in a suspended state if there are fouractive processes on the peer controller. The suspended processes are resumedon the peer controller when the number of active processes falls below four.Disk Group OperationsRAID Level MigrationYou can migrate from one RAID level to another depending on yourrequirements. For example, fault-tolerant characteristics can be added to astripe set (RAID 0) by converting it to a RAID 5 set. MDSM providesinformation about RAID attributes to assist you in selecting the appropriateRAID level. You can perform a RAID level migration while the system is stillrunning and without rebooting, which maintains data availability.Segment Size MigrationSegment size refers to the amount of data (in KB) that the storage arraywrites on a single physical disk in a virtual disk before writing data on the nextphysical disk. Valid values for the segment size are 8 KB, 16 KB, 32 KB, 64 KB,128 KB, 256 KB, and 512 KB.Dynamic segment size migration enables the segment size of a given virtualdisk to be changed. A default segment size is set when the virtual disk iscreated, based on such factors as the RAID level and expected usage. You canchange the default value if segment size usage does not match your needs.
