Setup Guide

Presenting PowerStore Cluster Volumes to the Linux Host
Specify Linux as the operating system when presenting PowerStore cluster volumes to the Linux host.
● When adding host groups and hosts to allow Linux hosts to access PowerStore cluster volumes, specify Linux as the
operating system for the newly created hosts.
● Setting the operating system of the host is required for optimal interoperability and stability of the host with PowerStore
cluster storage. You can adjust the setting while the host is online and connected to the PowerStore cluster with no I/O
impact.
Partition Alignment in Linux
When using disk partitions with a Linux host attached to a PowerStore cluster, alignment is recommended. Follow these
guidelines to align disk partitions.
To align partitions on PowerStore cluster volumes that are presented to Linux hosts, use the default value (2048). Then, create
a partition using the fdisk command to ensure that the file system is aligned.
When you perform partition alignment, the logical device (/dev/mapper/<naa-name>) should be used rather than the
physical device (/dev/<device>). When multipathing is not used (for example in a virtual machine), the physical device
should be used.
The following example demonstrates using the fdisk command to create an aligned partition on a PowerStore cluster volume.
[root@lg114 ~]# fdisk -c -u /dev/mapper/ 368ccf098003f1461569ea4750e9dac50
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x12d4e90c Changes will remain
in memeory only, until you decide to write them. After that, of course, the previous
content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
Command (m for help): p
Disk /dev/mapper/3514f0c5b12a00004: 1649.3 GB, 1649267441664 bytes
255 heads, 63 sectors/track, 200512 cylinders, total 3221225472 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes I/O size
(minimum/optimal): 16384 bytes / 65536 bytes Disk identifier: 0x12d4e90c
Device Boot Start End Blocks Id System
In this mode, rather than using "cylinders" for creating partitions, the fdisk command uses sectors, which are a direct mapping
to the LBA space of the cluster. Thus, to verify that the partition is aligned, simply verify that the starting sector number is a
multiple of 16 (16 sectors, at 512 bytes each, is 8 KB). The fdisk command defaults to a starting sector for the first partition
of 2048, which is divisible by 16, and thus is correctly assigned.
Creating a File System
When creating a file system with PowerStore cluster storage, use its default block size, and disable UNMAP during creation.
It is recommended to create the file system using its default block size (using a non-default block size may lead to unexpected
behavior). Refer to your operating system and file system documentation.
NOTE:
Creating a file system with UNMAP enabled on a host connected to PowerStore may result in an increased amount
of write I/Os to the storage subsystem. It is highly recommended to disable UNMAP during file system creation.
To disable UNMAP during file system creation:
● When creating a file system using the mke2fs command - Use the "-E nodiscard" parameter.
● When creating a file system using the mkfs.xfs command - Use the "-K" parameter.
For a more efficient data utilization and better performance, use Ext4 file system with PowerStore cluster storage instead of
Ext3. For details on converting to Ext4 file system (from either Ext3 or Ext2), refer to https://ext4.wiki.kernel.org/index.php/
UpgradeToExt4.
NOTE: File system configuration and management are out of the scope of this document.
38 Host Configuration for Linux