4.4. mkfs - Stripe Alignment

Aligning file data I/Os on stripe width boundaries can significantly improve performance on large RAIDs

A 2MB write to filesystem with a 2MB stripe width and 512KB stripe unit will result in four I/Os, one to each lun. Without alignment this would often require two I/Os to one disk, and one I/O to the other three, taking longer than it should.

To create a filesystem with a stripe unit of 1MB for an 8+1 RAID you would use:

mkfs.xfs -d sunit=2048,swidth=16384 device

mkfs.xfs -d su=1m,sw=8m device

Note

xfsprogs 3.1.0 and newer will use the blkid library to correctly identify stripe geometry for lvm, md, and some hardware raid devices which export this information