Make an XFS filesystem using default options. Note: the -f option is required to force mkfs to overwrite an existing filesystem.

# mkfs -t xfs -f /dev/sda4
meta-data=/dev/sda4              isize=256    agcount=16, agsize=461617 blks
         =                       sectsz=512   attr=0
data     =                       bsize=4096   blocks=7385872, imaxpct=25
         =                       sunit=0      swidth=0 blks, unwritten=1
naming   =version 2              bsize=4096
log      =internal log           bsize=4096   blocks=3606, version=1
         =                       sectsz=512   sunit=0 blks
realtime =none                   extsz=65536  blocks=0, rtextents=0

Mount the filesystem:

# mkdir mnt
# mount /dev/sda4 /mnt
# mount
/dev/sda2 on / type xfs (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
tmpfs on /dev/shm type tmpfs (rw)
devpts on /dev/pts type devpts (rw,mode=0620,gid=5)
usbfs on /proc/bus/usb type usbfs (rw)
/dev/sda4 on /mnt type xfs (rw)

Query the filesystem's parameters:

# xfs_info /mnt
meta-data=/dev/sda4              isize=256    agcount=16, agsize=461617 blks
         =                       sectsz=512   attr=0
data     =                       bsize=4096   blocks=7385872, imaxpct=25
         =                       sunit=0      swidth=0 blks, unwritten=1
naming   =version 2              bsize=4096
log      =internal               bsize=4096   blocks=3606, version=1
         =                       sectsz=512   sunit=0 blks
realtime =none                   extsz=65536  blocks=0, rtextents=0

Unmount the filesystem:

# umount /mnt