metrics: removal of reference in the documentation to the dax test.

This PR removes the reference in the documentation to the DAX
subtest of the FIO benchmark, because this metric is currently
WIP.

Fixes: kata-containers#8159

Signed-off-by: David Esparza <david.esparza.borquez@intel.com>

tests/metrics/storage/README.md

@@ -16,12 +16,16 @@ $ bash storage/blogbench.sh
 ```
 ## `fio` test
 
-The `fio` test utilises the [fio tool](https://github.com/axboe/fio), configured
-to perform measurements upon a single test file.
+The `fio` test utilizes the [fio tool](https://github.com/axboe/fio), configured to perform measurements upon a single test file.
 
-The test configuration used by the script can be modified by setting a number of
-environment variables to change or over-ride the test defaults.
+The test spawns 8 jobs that exercise the I/O types `sequential read`, `random read`, `sequential write` and `random write`, while collecting
+data using a block size of 4 Kb, an I/O depth of 2, and uses the `libaio` engine on a workload with a size of 10 gigabytes for a period of
+10 seconds on each I/O type.
 
-## DAX `virtio-fs` `fio` Kubernetes tests
+The results show the average bandwidth and average number of IOPS per I/O type in JSON format.
 
-[Test](fio-k8s/README.md) to compare the use of DAX option in `virtio-fs`.
+The `fio` test can be run by hand, for example:
+```
+$ cd metrics
+$ bash storage/fio_test.sh
+```