XFS File system in trouble

[Martin Steigerwald]

Am Dienstag, 28. Juli 2015, 22:12:00 schrieb Martin Papik:
> >>> Hmm, I guess the file size exceeds the capabilities of the root
> >>> fs, even if there might ultimately be enough space to restore
> >>> the metadump.
> >> 
> >> I wouldn't think so, at least not fundamentally. It's ext4. It's
> >> certainly not big enough to hold an 18T file system, though, and
> >> perhaps that is what xfs_restore is checking.
> > 
> > No, it's just failing to write any data at an 18T offset.
> > 
> > The ext4 filesystem (with 4k blocks) is limited to a 16T maximum
> > file offset; you won't be able to restore a (sparse) 18T
> > filesystem image onto an ext4 filesystem.

> How about this?
> 
> qemu-img create -f qcow2 test 32T
> qemu-nbd -c /dev/nbd0 test
> xfs_mdrestore -g md0.metadump /dev/nbd0

I used an XFS filesystem with truncate command to create an 1 EiB XFS 
filesystem in a sparse file for testing a year or two ago. It took about 18 
GiB for writing metadata and journal at mkfs.xfs time.

With df -h you get "1E" and with df without option you get an really large 
number :)

Thanks,
-- 
Martin