On Feb 27, 2014, at 9:21 PM, Dave Chinner <david@xxxxxxxxxxxxx> wrote: >> >> http://lists.centos.org/pipermail/centos/2011-April/109142.html > > <sigh> > > No, he didn't fill it with 16TB of data and then have it fail. He > made a new filesystem *larger* than 16TB and tried to mount it: > > | On a CentOS 32-bit backup server with a 17TB LVM logical volume on > | EMC storage. Worked great, until it rolled 16TB. Then it quit > | working. Altogether. /var/log/messages told me that the > | filesystem was too large to be mounted. Had to re-image the VM as > | a 64-bit CentOS, and then re-attached the RDM's to the LUNs > | holding the PV's for the LV, and it mounted instantly, and we > | kept on trucking. > > This just backs up what I told you originally - that XFS has always > refused to mount >16TB filesystems on 32 bit systems. That isn't how I read that at all. It was a 17TB LV, working great (i.e. mounted) until it was filled with 16TB, then it quite working and could not subsequently be mounted until put on a 64-bit kernel. I don't see how it's "working great" if it's not mountable. > >>> I said that it was limited on XFS, not that the limit was a >>> result of a user making a filesystem too large and then finding >>> out it didn't work. Indeed, you can't do that on XFS - mkfs will >>> refuse to run on a block device it can't access the last block >>> on, and the kernel has the same "can I access the last block of >>> the filesystem" sanity checks that are run at mount and growfs >>> time. >> >> Nope. What I reported on the XFS list, I had used mkfs.xfs while >> running 32bit kernel on a 20TB virtual disk. It did not fail to >> make the file system, it failed only to mount it. > > You said no such thing. All you said was you couldn't mount a > filesystem > 16TB - you made no mention of how you made the fs, what > the block device was or any other details. All correct. It wasn't intended as a bug report, it seemed normal. What I reported = the mount failure. VBox 25TB VDI as a single block device, as well as 5x 5TB VDIs in an 20TB linear LV, as well as a 100TB virtual size LV using LVM thinp - all can be formatted with default mkfs.xfs with no complaints. 3.13.4-200.fc20.i686+PAE xfsprogs-3.1.11-2.fc20.i686 > >> It was the same >> booted virtual machine, I created the file system and immediately >> mounted it. If you want the specifics, I'll post on the XFS list >> with versions and reproduce steps. > > Did you check to see whether the block device silently wrapped at > 16TB? There's a real good chance it did - but you might have got > lucky because mkfs.xfs uses direct IO and *maybe* that works > correctly on block devices on 32 bit systems. I wouldn't bet on it, > though, given it's something we don't support and therefore never > test…. I did not check to see if any of the block devices silently wrapped, I don't know how to do that although I have a strace of the mkfs on the 100TB virtual LV here: https://dl.dropboxusercontent.com/u/3253801/mkfsxfs32bit100TBvLV.txt Chris Murphy-- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
