I am formatting a couple of 60G Logical Volumes (
vg01-monitoring) in one of our servers. These partitions will hold a large number of small files, so I want them with more than the default number of inodes.
root@mercury20:/root : lvs /dev/mapper/vg01-logs /dev/mapper/vg01-monitoring LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert logs vg01 -wi-ao---- 60.00g monitoring vg01 -wi-ao---- 60.00g
vg01-logs is to be mounted on
/logs. I formatted it in
-i 1024 (bytes-per-inode) option to create maximum number of inodes and as expected the partition had 62914560 inodes after formatting.
mkfs.ext4 -i 1024 /dev/vg01/logs
Post formatting and mounting:
root@mercury20:/root : tune2fs -l /dev/mapper/vg01-logs | egrep 'Inode count|Inode size' Inode count: 62914560 Inode size: 256 root@mercury20:/root : df -h /logs Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg01-logs 45G 61M 42G 1% /logs
Now, after mounting the partition,
df -h outputs the size of this 60G Logical Volume partition as 45G. ie. 15G is gone. Since inodes are of size 256 bytes, and 15G being
62914560*256 bytes, is that space (15G) is reserved for inode creation and therefore missing from
The other Logical Volume
vg01-monitoring, which is to be mounted on
/monitoring, was formatted in
mkfs.xfs with default options. The partition was created with the same number of inodes (62914560) as the
ext4 partition, but here, post formatting and mounting,
df -h shows the size of the drive as the original 60G. No missing 15G.
xfs_info shows the size of the inode in this XFS partition as 256 bytes which is the same as in
root@mercury20:/root : mkfs.xfs -f /dev/mapper/vg01-monitoring root@mercury20:/root : df -h /monitoring Filesystem Size Used Avail Use% Mounted on /dev/mapper/vg01-monitoring 60G 33M 60G 1% /monitoring root@mercury20:/root : xfs_info /dev/mapper/vg01-monitoring meta-data=/dev/mapper/vg01-monitoring isize=256 agcount=4, agsize=3932160 blks
Here are my questions:
1) In the first case, that of the
ext4 partition, is my assumption that
df -h shows the space available as only 45G since 15G out of the 60G is reserved for inodes correct?
2) If my above assumption is correct, then why do XFS partition show 60G instead of 45G? Does it mean XFS will show the size consumed by inodes as 'Used' only when the inodes are created? Which at the end means, the effective space for user data on both the drives would be 45G though the XFS shows 60G available?
The OS is SUSE Linux Enterprise Server 12 (x86_64).
root@mercury20:/root : cat /etc/os-release NAME="SLES" VERSION="12-SP1" VERSION_ID="12.1"