How to Expand Virtual Disk Capacity and Change RAID Levels Online with Dell iDRAC9

Online Disk Expansion on Dell 14‑Generation Servers

Dell 14G servers equipped with iDRAC9 allow hot‑adding disks and expanding storage without rebooting or interrupting workloads. The process is performed through the iDRAC web interface, which operates out‑of‑band.

Scenario 1 – Existing RAID group has free capacity

Navigate to the iDRAC storage view.

Select the virtual disk to enlarge and click Edit Disk Capacity .

Enter the new size (e.g., increase from 300 GB to 500 GB) and click Apply .

The virtual disk is resized online; the operating system can immediately use the additional space after rescanning the SCSI bus or running partprobe / fdisk -l as needed.

Scenario 2 – RAID group lacks free space

In the iDRAC storage view, click +Add Physical Disk and select unused disks (e.g., Physical Disk 0:1:1 and 0:1:2).

The selected disks are added to the existing RAID group, increasing its raw capacity.

After the addition completes, repeat the steps from Scenario 1 to enlarge the virtual disk.

Online RAID Level Migration

iDRAC9 can change the RAID level of an existing virtual disk while the system remains operational.

Ensure the required number of disks for the target RAID level are present (e.g., at least three disks for RAID 5).

Select the virtual disk, choose Change RAID Level , pick the new level, and click Apply .

The migration runs in the background; completion time depends on disk size and server load.

Additional Out‑of‑Band Disk Management Functions

Create new RAID groups from newly added physical disks.

Modify virtual‑disk cache policies (write‑back, write‑through, etc.) online.

These capabilities, previously only available via in‑band tools such as Dell OpenManage Server Administrator (OMSA), are now accessible through iDRAC9, enabling administrators to manage storage without service interruption.