Expanding the file system based on xfs in LVM

I have never been exposed to CentOS 7 before and do not understand the features it has changed. I came across LVM in centos  7 by chance. The method of creating LVM is the same as that in 6, but the expansion of LVM is a little different. Use the previous method. After the expansion, it never took effect. It took me a long time to figure out how to expand it. Xfs is the default file system type of CentOS7, and different file system types have different creation, inspection, and adjustment commands .

Xfs is the default file system type of CentOS7, and different file system types have different creation, inspection, and adjustment commands .

In the xfs file system, the partition can only be increased but not reduced.

[root@localhost ~]# ls /lib//modules/3.10.0-229.20.1.el7.x86_64/kernel/fs #View all file system types supported by the kernel 
binfmt_misc.ko ceph dlm fat gfs2 lockd nfs_common overlayfs udf 
btrfs cifs exofs fscache isofs mbcache.ko nfsd pstore xfs 
cachefiles cramfs ext4 fuse jbd2 nfs nls squashfs

I have previously created a new partition and added it to vg, and the physical boundaries have also been expanded.

When extending the logical boundary, the error message is as follows:

[root@localhost ~]# resize2fs -p /dev/mapper/centos-root      
resize2fs 1.42.9 (28-Dec-2013) 
resize2fs: Bad magic number in super-block when trying to open /dev/mapper/centos-root 
A valid file system superblock was not found.

First I thought of using fsck to repair it, but it didn’t work. After seeing the error message, I realized that the xfs file needs to be repaired using xfs_repair.

[root@localhost ~]# fsck /dev/mapper/centos-root      
fsck，来自 util-linux 2.23.2
If you wish to check the consistency of an XFS filesystem or
repair a damaged filesystem, see xfs_repair(8).

Then I tried to repair it, but it didn't work. It needs to be uninstalled to repair it, and this file system is mounted under /, so don't even think about it.

[root@localhost ~]# xfs_repair /dev/mapper/centos-root 
xfs_repair: /dev/mapper/centos-root contains a mounted filesystem
xfs_repair: /dev/mapper/centos-root contains a mounted and writable filesystem
 
fatal error -- couldn't initialize XFS library

Finally, after some research on the Internet, I found out that after the logical expansion of the xfs file system, there is still one more step to complete:

[root@localhost ~]# lvs 
  LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert 
  root centos -wi-ao---- 95.00g                                                     
  swap centos -wi-ao---- 3.88g              
[root @localhost ~]# df -lh 
file system capacity used available used % mount point 
/dev/mapper/centos-root 46G 42G 4.5G 91% / ------------>46G 
devtmpfs 1.9G 0 1.9G 0% /dev 
tmpfs 1.9G 164K 1.9G 1% /dev/shm 
tmpfs 1.9G 8.7M 1.9G 1% /run 
tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup  
/dev/sda1 497M 208M 290M 42% /boot                                       
[root@localhost ~]# xfs_growfs /dev/mapper/centos-root #Perform adjustments, this step is required after expansion
meta-data=/dev/mapper/centos-root isize=256 agcount=4, agsize=2987776 blks 
         = sectsz=512 attr=2, projid32bit=1 
         = crc=0 finobt=0 
data = bsize=4096 blocks=11951104, imaxpct=25 
         = sunit=0 swidth=0 blks 
naming =version 2 bsize=4096 ascii-ci=0 ftype=0 
log =internal bsize=4096 blocks=5835, version=2 
         = sectsz=512 sunit=0 blks, lazy- count=1 
[root@localhost ~]# df -lh 
file system capacity used available used % mount point 
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 11951104 to 24903680
 
/dev/mapper/centos-root 95G 42G 54G 44% / ----------> Completed expansion of 
devtmpfs 1.9G 0 1.9G 0% /dev 
tmpfs 1.9G 164K 1.9G 1% /dev /shm 
tmpfs 1.9G 8.7M 1.9G 1% /run 
tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup 
/dev/sda1 497M 208M 290M 42% /boot

Commonly used commands related to xfs

xfs_admin: adjust various parameters of the xfs file system   
xfs_copy: copy the contents of the xfs file system to one or more target systems (in parallel mode)   
xfs_db: debug or detect the xfs file system (view file system fragments, etc.)   
xfs_check: detect the xfs file system Integrity   
xfs_bmap: View the block map of a file   
xfs_repair: Attempt to repair a damaged xfs file system   
xfs_fsr   
:   
Defragment Medium   
xfs_mdrestore: restore metadata (metadata) from a file to the xfs file system   
xfs_growfs: resize an xfs file system (can only be extended)   
xfs_freeze pause (-f) and resume (-u) xfs file system 
xfs_logprint: print xfs File system log   
xfs_mkfile: create xfs file system   
xfs_info: query file system details   
xfs_ncheck: generate pathnames from i-numbers for XFS   
xfs_rtcp: XFS real-time copy command    
xfs_io: debug xfs I/O path

Note:
After using the mke2fs command on the Xfs file system, it becomes ext2. You need to modify the corresponding file system type in the file /etc/fstab!