Errors during hole punching test
Kudu requires hole punching capabilities in order to be efficient. Hole punching support depends upon your operation system kernel version and local filesystem implementation.
RHEL or CentOS 6.4 or later, patched to kernel version of 2.6.32-358 or later. Unpatched RHEL or CentOS 6.4 does not include a kernel with support for hole punching.
Ubuntu 14.04 includes version 3.13 of the Linux kernel, which supports hole punching.
Newer versions of the ext4 and xfs filesystems support hole punching. Older versions that do not support hole punching will cause Kudu to emit an error message such as the following and to fail to start:
Error during hole punch test. The log block manager requires a filesystem with hole punching support such as ext4 or xfs. On el6, kernel version 2.6.32-358 or newer is required. To run without hole punching (at the cost of some efficiency and scalability), reconfigure Kudu with --block_manager=file. Refer to the Kudu documentation for more details. Raw error message follows.
Without hole punching support, the log block manager is unsafe to use. It won’t ever delete blocks, and will consume ever more space on disk.
If you can’t use hole punching in your environment, you can still try Kudu. Enable
the file block manager instead of the log block manager by adding the
--block_manager=file flag to the commands you use to start the master
and tablet servers. The file block manager does not scale as well as the log block