Release Notes

Linux setup and configuration

27 Dell EMC PowerVault ME4 Series and Linux | 3924-BP-L

3.5.1 File system layout

The file system can be created on top of a LUN, a LUN partition, or a logical volume within LVM. Dell EMC

recommends using the whole LUN without a partition or logical volume in LVM for ease of management. If the

file systems reside in LVM, follow the LVM guidelines when creating and grouping multiple file systems.

3.5.2 File system mount options

When mounting a file system, consider the following options and guidelines:

• Identify the file system by its UUID or LVM LV device in the /etc/fstab file. Avoid using any non-

persistent device paths such as /dev/sd*.

• UUID can be queried by blkid command.

# blkid /dev/mapper/vgme4-lvme4

/dev/mapper/vgme4-lvme4: UUID="ad40e2c2-8ce0-42c6-94bb-9854b73f5336" TYPE="xfs"

• Include nofail in the mount option if the Linux operating system experiences mount issue during

system boot. This prevents interruption during the boot process which requires manual intervention.

• For the xfs file system, the file system check (fsck option) should be disabled in /etc/fstab because it

does not perform any check or repair automatically during boot time. The xfs journaling feature

ensures the file system integrity and data is in a consistent state after abrupt shutdown. If a manual

repair or check is necessary, use the xfs_repair utility to repair damaged file system.

• To disable fsck check, set a value of 0 in the sixth field for the file system entry in /etc/fstab. Here is

an example of an xfs file system entry in /etc/fstab:

UUID="ad40e2c2-8ce0-42c6-94bb-9854b73f5336" /me4_fs xfs defaults,discard,nofail 0 0

3.5.3 Expand storage for the file system

Certain file system types, such as ext4 and xfs, support the online resize operation. The following procedure

outlines the general steps to resize a file system online assuming non-partition LUNs are used.

1. Expand the size of existing LUNs in ME Storage Manager.

2. Perform a SCSI scan on the host systems, refresh the partition table on each LUN path, and reload

multipath devices.

# rescan-scsi-bus.sh --resize

3. Reload the multipath devices. Skip this step if multipath devices are disabled.

# multipathd -k"resize map mpathb"

4. Expand the logical volume if the file system is on top of LVM. Skip this step if the file system does not

reside in LVM.

# lvresize –L $NEW_SIZE /dev/vgme4/lvme4

5. Extend the file system size to the maximum size, automatically and online

# xfs_growfs –d /me4_fs (for xfs)

# resize2fs /dev/mapper/mpathb (for ext4)