I recently set up my first software raid with mdadm and after adding more disks to the raid I am unable to resize the filesystem to the full size of the raid. I created a single (~16TB) filesystem on /dev/md0 via:
mkfs.ext4 -v -b 4096 -t huge -E stride=128,stripe-width=256 /dev/md0
I then waited painfully for a couple of days as all of the data from the old raid copied over to the new raid; I moved over the disks and grew the raid and then finally I:
resize2fs -p /dev/md0
Which informs me that
resize2fs 1.42 (29-Nov-2011) resize2fs: /dev/md0: The combination of flex_bg and !resize_inode features is not supported by resize2fs
I lack any understanding of exactly what these two features are for or why the combination is troublesome, so against my better judgement I tried to add resize_inode:
tune2fs -O +resize_inode /dev/md0
But I got shot down:
Setting filesystem feature 'resize_inode' not supported.
And I'm not brave enough to try to remove flex_bg as I really don't want to do anything that might put my data at risk. I'm running Ubuntu 12.04 with the 3.5.1 kernel:
Linux critter 3.5.1-030501-generic #201208091310 SMP Thu Aug 9 17:11:48 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
I tested resize2fs again with v1.42.5 (the latest available release) to no avail. So, to be clear, my question is: how can I resize this ext4 filesystem to the size of the raid (without recreating it, preferably)?
Edit: here's some filesystem information that might be helpful.
tune2fs -l /dev/md0 tune2fs 1.42 (29-Nov-2011) Filesystem volume name: <none> Last mounted on: /media/Bigger Filesystem UUID: baecfa03-74c1-42ad-8e19-3b823f05f502 Filesystem magic number: 0xEF53 Filesystem revision #: 1 (dynamic) Filesystem features: has_journal ext_attr dir_index filetype extent 64bit flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize Filesystem flags: signed_directory_hash Default mount options: user_xattr acl Filesystem state: clean Errors behavior: Continue Filesystem OS type: Linux Inode count: 274700288 Block count: 4395202560 Reserved block count: 219760128 Free blocks: 247712956 Free inodes: 274636266 First block: 0 Block size: 4096 Fragment size: 4096 Blocks per group: 32768 Fragments per group: 32768 Inodes per group: 2048 Inode blocks per group: 128 RAID stride: 128 RAID stripe width: 768 Flex block group size: 16 Filesystem created: Fri Aug 17 02:54:50 2012 Last mount time: Mon Aug 20 02:21:51 2012 Last write time: Mon Aug 20 02:25:07 2012 Mount count: 3 Maximum mount count: -1 Last checked: Fri Aug 17 02:54:50 2012 Check interval: 0 (<none>) Lifetime writes: 16 TB Reserved blocks uid: 0 (user root) Reserved blocks gid: 0 (group root) First inode: 11 Inode size: 256 Required extra isize: 28 Desired extra isize: 28 Journal inode: 8 Default directory hash: half_md4 Directory Hash Seed: b357ba49-60b1-4c55-837f-a70c8285a8f5 Journal backup: inode blocks