Dell MD3220, MD3200 Device Mapper Configuration Steps, Scan for Newly Added Virtual Disks, 181

Device Mapper Configuration Steps

To complete the DM multipathing configuration and make the storage available to the Linux host server:

1Scan for virtual disks. See "Scan for Newly Added Virtual Disks" on page 181.

2Display the multipath device topology. See "Display the Multipath Device Topology Using the Multipath Command" on page 181.

3Create a partition on a multipath device node. See "Create a New fdisk Partition on a Multipath Device Node" on page 183.

4Add a partition to DM. See "Add a New Partition to Device Mapper" on page 183.

5Create a file system on a DM partition. See "Create a File System on a Device Mapper Partition" on page 184.

6Mount a DM partition. See "Mount a Device Mapper Partition" on page 184.

The following instructions show how to complete each of these steps.

In the following command descriptions <x> is used to indicate where a substitution must be made. On RHEL systems <x> is the number assigned to the device. On SLES systems <x> is the letter(s) assigned to the device.

Scan for Newly Added Virtual Disks

The rescan_dm_devs command scans the host server system looking for existing and newly added virtual disks mapped to the host server.

# rescan_dm_devs

If an array virtual disk (VD) is mapped to the host server at a later time, the rescan_dm_devices command must be run again to make the VD a visible LUN to the operating system.

Display the Multipath Device Topology Using the Multipath Command

The multipath command adds newly scanned and mapped virtual disks to the Device Mapper tables and creates entries for them in the /dev/mapper directory on the host server. These devices are the same as any other block devices in the host.

To list all the multipath devices, run the following command:

Configuration: Device Mapper Multipath for Linux

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