On Wed, Jul 9, 2014 at 1:27 PM, Lamar Owen <[email protected]> wrote: > > I don't recall if I had to specify that option or not with CentOS 5.10: > +++++++++++++++++++++++++++ > [root@backup-rdc ~]# df -h > Filesystem Size Used Avail Use% Mounted on > ... > /dev/mapper/plates-cx3--80 > 27T 26T 805G 98% /opt/plates > /dev/mapper/vg_opt-lv_backups > 5.8T 5.4T 365G 94% /opt/backups > [root@backup-rdc ~]# blkid
You are getting a little bit lucky, I think... The failure happens when the first 16TB of the block device (as opposed to file system) are in use. Since XFS allocates blocks from allocation groups all over the disk, it is improbable that the first 16TB is ever actually in use until the entire file system fills up. We have had a few dozen ~30TB XFS storage systems in the field for the past several years, and I only ever saw this failure once. At the time the file system was maybe 85% full. But then our files are typically in the 100s of gigabytes, which perhaps makes it more likely to trigger (?) I swear I am not making up this problem; see e.g. http://www.doc.ic.ac.uk/~dcw/xfs_16tb/ Anyway, inode64 is the recommended mount option for large XFS file systems unless you have some specific legacy need (like exporting via NFSv2 to 32-bit Solaris... guess how I know) Cheers. - Pat
