Learn xfs file system commands to create, grow, repair xfs file system along with command examples.
In our other article, we walked you through what is xfs, features of xfs, etc. In this article, we will see some frequently used xfs administrative commands. We will see how to create xfs filesystem, how to grow xfs filesystem, how to repair the xfs file system, and check xfs filesystem along with command examples.
Create XFS filesystem
mkfs.xfs command is used to create xfs filesystem. Without any special switches, command output looks like one below –
root@kerneltalks # mkfs.xfs /dev/xvdf
meta-data=/dev/xvdf isize=512 agcount=4, agsize=1310720 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0, sparse=0
data = bsize=4096 blocks=5242880, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
Note: Once the XFS filesystem is created it can not be reduced. It can only be extended to a bigger size.
Resize XFS file system
In XFS, you can only extend the file system and can not reduce it. To grow XFS file system use xfs_growfs. You need to specify a new size of mount point along with -D switch. -D takes argument number as file system blocks. If you don’t supply -D switch, xfs_growfs will grow the filesystem to the maximum available limit on that device.
root@kerneltalks # xfs_growfs /dev/xvdf -D 256
meta-data=/dev/xvdf isize=512 agcount=4, agsize=720896 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=2883584, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data size 256 too small, old size is 2883584
In the above output, observe the last line. Since I supplied a new size smaller than the existing size, xfs_growfs didn’t change the filesystem. This shows you can not reduce the XFS file system. You can only extend it.
root@kerneltalks # xfs_growfs /dev/xvdf -D 2883840
meta-data=/dev/xvdf isize=512 agcount=4, agsize=720896 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=2883584, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 2883584 to 2883840
Now, I supplied new size 1 GB extra and it successfully grew the file system.
1 GB blocks calculation :
The current filesystem has bsize=4096 i.e. block size of 4MB. We need 1 GB i.e. 256 blocks. So add 256 in a current number of blocks i.e. 2883584 which gives you 2883840. So I used 2883840 as an argument to -D switch.
Repair XFS file system
File system consistency check and repair of XFS can be performed using xfs_repair command. You can run the command with -n switch so that it will not modify anything on the filesystem. It will only scans and reports which modifications to be done. If you are running it without -n switch, it will modify the file system wherever necessary to make it clean.
Please note that you need to un-mount the XFS filesystem before you can run checks on it. Otherwise, you will see the below error.
root@kerneltalks # xfs_repair -n /dev/xvdf
xfs_repair: /dev/xvdf contains a mounted filesystem
xfs_repair: /dev/xvdf contains a mounted and writable filesystem
fatal error -- couldn't initialize XFS library
Once successfully un-mounting file system you can run command on it.
root@kerneltalks # xfs_repair -n /dev/xvdf
Phase 1 - find and verify superblock...
Phase 2 - using internal log
- zero log...
- scan filesystem freespace and inode maps...
- found root inode chunk
Phase 3 - for each AG...
- scan (but don't clear) agi unlinked lists...
- process known inodes and perform inode discovery...
- agno = 0
- agno = 1
- agno = 2
- agno = 3
- agno = 4
- process newly discovered inodes...
Phase 4 - check for duplicate blocks...
- setting up duplicate extent list...
- check for inodes claiming duplicate blocks...
- agno = 0
- agno = 1
- agno = 2
- agno = 3
- agno = 4
No modify flag set, skipping phase 5
Phase 6 - check inode connectivity...
- traversing filesystem ...
- traversal finished ...
- moving disconnected inodes to lost+found ...
Phase 7 - verify link counts...
No modify flag set, skipping filesystem flush and exiting.
In the above output you can observe, in each phase command shows possible modification which can be done to make the file system healthy. If you want the command to do that modification during the scan then run the command without any switch.
root@kerneltalks # xfs_repair /dev/xvdf
Phase 1 - find and verify superblock...
Phase 2 - using internal log
- zero log...
- scan filesystem freespace and inode maps...
- found root inode chunk
Phase 3 - for each AG...
- scan and clear agi unlinked lists...
- process known inodes and perform inode discovery...
- agno = 0
- agno = 1
- agno = 2
- agno = 3
- agno = 4
- process newly discovered inodes...
Phase 4 - check for duplicate blocks...
- setting up duplicate extent list...
- check for inodes claiming duplicate blocks...
- agno = 0
- agno = 1
- agno = 2
- agno = 3
- agno = 4
Phase 5 - rebuild AG headers and trees...
- reset superblock...
Phase 6 - check inode connectivity...
- resetting contents of realtime bitmap and summary inodes
- traversing filesystem ...
- traversal finished ...
- moving disconnected inodes to lost+found ...
Phase 7 - verify and correct link counts...
done
In the above output, you can observer xfs_repair command is executing possible filesystem modification as well to make it healthy.
Check XFS version and details
Checking the xfs file system requires it to un-mount. Run xfs_db command on its device path and once you entered xfs_db prompt, run version command.
xfs_db command normally used for examining the XFS file system. version command used to enable features in the file system. Without any argument, the current version and feature bits are printed
root@kerneltalks # xfs_db /dev/xvdf1
xfs_db: /dev/xvdf1 contains a mounted filesystem
fatal error -- couldn't initialize XFS library
root@kerneltalks # umount /shrikant
root@kerneltalks # xfs_db /dev/xvdf1
xfs_db> version
versionnum [0xb4a5+0x18a] = V5,NLINK,DIRV2,ALIGN,LOGV2,EXTFLG,MOREBITS,ATTR2,LAZYSBCOUNT,PROJID32BIT,CRC,FTYPE
xfs_db> quit
To view details of the XFS file system like block size and number of blocks which helps you in calculating new block number for growing XFS file system, use xfs_info without any switch.
root@kerneltalks # xfs_info /shrikant
meta-data=/dev/xvdf isize=512 agcount=5, agsize=720896 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=2883840, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
It displays all details as it shows while creating XFS file system
There are other XFS file system management commands which alter and manages its metadata. We will cover them in another article.
