Hello Nab, > So looking at the log provided off-list, the failure from the > underlying vfs_writev() call is a -EFBIG (File too large). This would > mean your hitting the underlying filesystem's per file maximum size, > assuming this is with ext[3,4] w/ 1k blocksize. Increasing the > ext[3,4] blocksize to 4k will get you up to 16 TB per file maximum > size limit. I confirm that on rtsos the reason is the maximum file size because it is ext3 with 4K which supports a maximum file size of 2TB according to http://en.wikipedia.org/wiki/Ext3 Creating a sparse file confirms this: (node-61) [~] dd if=/dev/zero of=junk3.sparse bs=1 count=0 seek=4T dd: failed to truncate to 4398046511104 bytes in output file `junk3.sparse': File too large (node-61) [~] dumpe2fs /dev/sda1 2> /dev/null | grep '^Block size:' Block size: 4096 (node-61) [~] mount | grep /dev/sda1 /dev/sda1 on / type ext3 (rw,relatime,errors=continue,user_xattr,acl,barrier=1,data=ordered) (node-61) [~] dumpe2fs /dev/sda1 2> /dev/null | grep '^Block size:' Block size: 4096 I tried to reran the test against rtsos with ext4 but failed: rtsnode1:~ # dmesg | grep -i ext4 [ 228.126289] EXT4-fs (sdb1): ext4 is supported in read-only mode only ... However xfs worked and I was able to create a 4TB sparse file: rtsnode1:/iscsi1 # dd if=/dev/zero of=junk3.sparse bs=1 count=0 seek=4T 0+0 records in 0+0 records out 0 bytes (0 B) copied, 3.2992e-05 s, 0.0 kB/s rtsnode1:/iscsi1 # ls -alh junk3.sparse -rw-r--r-- 1 root root 4.0T Feb 7 04:49 junk3.sparse And with rtsos on xfs I was able to create the file system on rtsos without a problem. However on the current Linux tip system I have ext4 with 4K blocksize and I can create a 4TB sparse file without a problem but it still fails to create a VMFS file system. The 'Create VMFS datastore' task runs for 10 minutes or longer without creating the file system. (node-62) [~] dd if=/dev/zero of=junk3.sparse bs=1 count=0 seek=4T 0+0 records in 0+0 records out 0 bytes (0 B) copied, 2.0527e-05 s, 0.0 kB/s (node-62) [~] ls -alh junk3.sparse -rw-r--r-- 1 sithglan sithglan 4.0T Feb 7 05:14 junk3.sparse (node-62) [~] dumpe2fs /dev/sda1 2> /dev/null | grep '^Block size:' Block size: 4096 (node-62) [~] dumpe2fs /dev/sdb1 2> /dev/null | grep '^Block size:' Block size: 4096 I used the following to create the LUN: set global auto_cd_after_create=false /backstores/fileio create shared-01.v101.gmvl.de /iscsi1/shared-01.v101.gmvl.de size=4T buffered=true /iscsi create iqn.2013-03.de.gmvl.v101.storage:shared-01.v101.gmvl.de /iscsi/iqn.2013-03.de.gmvl.v101.storage:shared-01.v101.gmvl.de/tpgt1/portals create <ip> /iscsi/iqn.2013-03.de.gmvl.v101.storage:shared-01.v101.gmvl.de/tpgt1/luns create /backstores/fileio/shared-01.v101.gmvl.de lun=10 /iscsi/iqn.2013-03.de.gmvl.v101.storage:shared-01.v101.gmvl.de/tpgt1/ set attribute authentication=0 demo_mode_write_protect=0 generate_node_acls=1 cache_dynamic_acls=1 saveconfig yes This time I enabled logging: echo 'module iscsi_target_mod +p' > /sys/kernel/debug/dynamic_debug/control echo 'module target_core_pscsi +p' > /sys/kernel/debug/dynamic_debug/control echo 'module target_core_file +p' > /sys/kernel/debug/dynamic_debug/control echo 'module target_core_iblock +p' > /sys/kernel/debug/dynamic_debug/control echo 'module target_core_mod +p' > /sys/kernel/debug/dynamic_debug/control https://thomas.glanzmann.de/tmp/node62_kern.log.bz2 (464K K) Cheers, Thomas -- To unsubscribe from this list: send the line "unsubscribe target-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html