How to create a XFS filesystem using a file

Sometimes we need to test on a XFS filesystem, just create a fake one using a file.

1.Create a 500MB temp file

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# dd if=/dev/zero of=openkbtest count=999999 999999+0 records in 999999+0 records out 511999488 bytes (512 MB) copied, 0.89366 seconds, 573 MB/s

1 2	# ls -altr openkbtest -rw-r--r-- 1 root root 511999488 Aug 16 14:31 openkbtest

2.Format the file to XFS filesystem

1	# /sbin/mkfs -t xfs -q openkbtest

3.Create a directory which will be the mount point

1	$ mkdir testmount

4.Check loopback device number,most likely we can start with loop0 if it is not used by others.

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$ cat /proc/mounts|grep loop $ cd /dev [dev]$ ls -altr|grep loop brw-r-----  1 root disk   7,     0 Jun 14 15:04 loop0 brw-r-----  1 root disk   7,     1 Jun 14 15:04 loop1 brw-r-----  1 root disk   7,     2 Jun 14 15:04 loop2 brw-r-----  1 root disk   7,     3 Jun 14 15:04 loop3 brw-r-----  1 root disk   7,     4 Jun 14 15:04 loop4 brw-r-----  1 root disk   7,     5 Jun 14 15:04 loop5 brw-r-----  1 root disk   7,     6 Jun 14 15:04 loop6 brw-r-----  1 root disk   7,     7 Jun 14 15:04 loop7

5.Mount it

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# mount -o loop=/dev/loop0 /data/tmp/openkbtest /data/xxx/testmount   # cat /proc/mounts|grep loop /dev/loop0 /data/xxx/testmount xfs rw,noquota 0 0