There are few issues with this test:

- you don't use oflag=direct or conv=fsync, so this may test copying data

to the host page cache, instead of writing data to storage

- This tests only sequential write, which is the best case for any kind of storage

- Using synchronous I/O - every write wait for the previous write completion

- Using single process

- 2g is too small, may test your cache performance

Try to test using fio - attached fio script that tests sequential and random io with

various queue depth.

You can use it like this:

fio --filename=/path/to/fio.data --output=test.out bench.fio

Test both on the host, and in the VM. This will give you more detailed

results that may help to evaluate the issue, and it may help Gluster

folks to advise on tuning your storage.

Nir