[CentOS] Ext4 mess .... and EXT4-fs error (device sdc): ext4_mb_generate_buddy

Hi,
I'm faced with a very strange behaviour:

Centos 6.5 server, Hardware ISCSI HBA from Emulex OneConnect, most
recent drivers and firmware from emulex installed.

Directly attached a 10G ISCSI Storage from QSan. Two Raid volumes, Raid
5, 8 Disks each at 2 TB so 14 TB each logic raid volume.

Both volumes are logged in and usable as sdb and sdc to the server.

Formatted with ext4  -m 0 -v /dev/sd...

Now I copied about 600 GB from an old server to one of the new volumes.
No problems at all.

But moving other data from the old server to the second volume shows the
error in the logs:

EXT4-fs error (device sdc): ext4_mb_generate_buddy: EXT4-fs: group 2592:
0 blocks in bitmap, 24544 in gd

group grows by 16.

But the more strange thing I realised today is, that all the data on the
first volume (on sdb) shows up on sdc as well + the new data too.

Now I'm totally confused and currently there are no more messages in the
system log.

The files on sdc don't show up on sdb!

If I do e.g. a md5sum on the files on both volumes they are the same as
is the contents of e.g. some textfiles I checked.

May be someone has an idea what might cause

a) the error and
b) why dose the data from sdb also shows up on sdc?

b) also occurred also with the original redhat/centos driver for the
ISCSI HBA.

May be I have to use partitions and not the whole device or LVM, ... xfs?

Other storages from Qsan dont show that problem and other storages with
bigger filesystems or e.g. xfs are o.k. too.


	confused regards . Götz