Disk full on linux server, blocks used is much less then blocks avalable

If this is an ext filesystem, the default root reserved space would be 5% of 1889811408 blocks, or 94490570 blocks. In other words, you have about 66GB more to delete before df will report free space available.

Use tune2fs -m 1 /dev/mapper/VolGro to decrease the reserved amount to 1%, or -r NNNN to set it to a specific number of blocks. There needs to be enough reserved space that logging can continue even after users have "filled" the disk (though if you're filling the disk as root, this won't save you from problems when the drive is absolutely full)

Other filesystems probably have reserved blocks as well, but the commands to adjust these will differ.

Run an fsck to see if the filesystem is damaged.