Dell PowerVault ME4 Series Storage System Administrator’s Guide

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Disk group options

The following options appear in the top section of the Add Disk Group panel:

Table 1. Disk group optionsDisk group options
Option	Description
Name	A disk group name is case-sensitive and can have a maximum of 32 bytes. The name cannot already exist in the system or include the following: " , < \
Type	When creating a disk group, select one following: Virtual: Shows options for a virtual disk group Linear: Shows options for a linear disk group Read Cache: Shows options for a read cache disk group
Pool (only appears for virtual and read-cache disk groups)	Select the name of the virtual pool (A or B) to contain the group.
Assign to (optional, only appears for linear disk groups)	For a system operating in Active-Active ULP mode, this option specifies the controller module to own the group. To let the system automatically load-balance groups between controller modules, select the Auto setting instead of Controller A or Controller B.
RAID Level	Select one of the following RAID levels when creating a virtual or linear disk group: RAID 1 – Requires 2 disks. RAID 5 – Requires 3-16 disks. RAID 6 – Requires 4-16 disks. RAID 10 – Requires 4-16 disks, with a minimum of two RAID-1 subgroups, each having two disks. RAID 50 – (only appears for linear disk groups). Requires 6-32 disks, with a minimum of two RAID-5 subgroups, each having three disks. ADAPT – Requires 12-128 disks. To create an NRAID, RAID-0, or RAID-3 (linear-only) disk group, you must use the CLI add disk-group command. For more information on this command, see the Dell PowerVault ME4 Series Storage System CLI Guide.
Number of Sub-groups (options only appear when RAID-10 or RAID-50 is selected)	Changes the number of sub-groups that the disk group should contain.
Chunk size (optional, only for linear non-ADAPT disk groups)	Specifies the amount of contiguous data, in KB, that is written to a group member before moving to the next member of the group. For NRAID and RAID 1, chunk-size has no meaning and is therefore not applicable. For RAID 50, this option sets the chunk size of each RAID-5 subgroup. The following chunk size options are available when creating a linear disk group: 64k 128k 256k 512k For a virtual group, the system uses one of the following chunk sizes, which cannot be changed: RAID 1: Not applicable RAID 5 and RAID 6: With 2, 4, or 8 non-parity disks: 512k. For example, a RAID-5 group with 3, 5, or 9 total disks or a RAID-6 group with 4, 6, or 10 total disks. Other configurations: 64k RAID 10: 512k
Online Initialization (only appears for linear disk groups)	Specifies whether the group is initialized online or offline. Online. When the Online Initialization check box is selected, you can use the group immediately after creating it while it is initializing. Because online uses the verify method to create the group, it takes longer to complete initializing than offline. Online initialization is fault-tolerant. Offline. When the Online Initialization check box is cleared, you must wait for the group initialization process to finish before using the group. However, offline takes less time to complete initializing than online.