[root@imysql ~]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/sdb1 xfs 19T 16T 2.4T 88% /backup</p><p>[root@imysql ~]# df -hi
Filesystem Inodes IUsed IFree IUse% Mounted on
/dev/sdb1 9.3G 3.4M 9.3G 1% /backup
Q: What is the inode64 mount option for?</p><p>By default, with 32bit inodes, XFS places inodes only in the first 1TB of a disk. If you have a disk with 100TB, all inodes will be stuck in the first TB. This can lead to strange things like "disk full" when you still have plenty space free, but there's no more place in the first TB to create a new inode. Also, performance sucks.
To come around this, use the inode64 mount options for filesystems >1TB. Inodes will then be placed in the location where their data is, minimizing disk seeks.
Beware that some old programs might have problems reading 64bit inodes, especially over NFS. Your editor used inode64 for over a year with recent (openSUSE 11.1 and higher) distributions using NFS and Samba without any corruptions, so that might be a recent enough distro.
