Originally developed at Silicon Graphics in 1993, the main purpose of XFS is to not only support the creation of large filesystems that will allow for metadata journaling, but to provide a technology that can be defragmented and enlarged while mounted and active. This information may or may not be of much use to you as a troubleshooter, but you should be aware that the default filesystem now employed by the most recent release of CentOS is known as XFS. If you did not customize the partitions to any great extent, then you may find that XFS is the filesystem you will be dealing with.

You can quickly confirm the structure of your system with the following command:

# df -Th

The preceding command (the disk size and partitions ignored) can result in something similar to the following output:

Filesystem              Type      Size  Used Avail Use% Mounted on
/dev/mapper/centos-root xfs        42G  1.5G   40G   4% /
devtmpfs                devtmpfs ...