[doc] Update README with new Parallax setup and branch

Author: NikosLasithiotakis

parallax_docs/run_fdb_hammer_with_parallax.md

@@ -1,38 +1,28 @@
 # Running fdb-hammer with Parallax
 
-1. **Edit the Configuration File**
-- Open the configuration file:
-  ```
-  fdb-kv/tests/fdb/etc/fdb/config.yaml
-  ```
-- Set the engine to either `parallax` or `daos`:
-  - `parallax` for Parallax engine
-  - `daos` for the dummy DAOS implementation that uses Parallax
+1. **Build fdb-kv**
+   - Read the `README.md` file in the project, and also check the `Dockerfile` to understand how to download the necessary dependencies for the project.
+   - **IMPORTANT:**
+     - Use both of these flags:
+       ```
+       -DUSE_PARALLAX=ON -DHAVE_PARALLAXFDB=ON
+       ```
 
-2. **Build fdb-kv**
-- Read the `README.md` file in the project, and also check the `Dockerfile` to understand how to download the necessary dependencies for the project.
-- **IMPORTANT:**
-  - To use the dummy DAOS implementation, set the following flag:
-    ```
-    -DUSE_PARALLAX=ON
-    ```
-  - To build with the Parallax engine, use both of these flags:
-    ```
-    -DUSE_PARALLAX=ON -DHAVE_PARALLAXFDB=ON
-    ```
-
-3. **Build Parallax**
+2. **Build Parallax**
+   - Checkout the branch `parallax_server_msg_rework`:
+     ```
+     git checkout parallax_server_msg_rework
+     ```
    - Build Parallax with the following flag enabled:
      ```
-     -DKV_MAX_SIZE_128K=ON
+     -DSEGMENT_SIZE=134217728 -DCUSTOM_KV_MAX_SIZE=4194304
      ```
    - Follow the Parallax build instructions if additional guidance is needed.
 
-4. **Start the Parallax Server**
+3. **Start the Parallax Server**
    - Run the Parallax server executable on `localhost:8080`.
    - Ensure the server is running before starting `fdb-hammer`.
 
-
-5. **Run the fdb-hammer executable**
+4. **Run the fdb-hammer executable**
    - Execute the `fdb-hammer` binary with the required parameters.
    - **IMPORTANT:** Always set the `nparams` parameter to `4` when running the executable.