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Using the Command Line Interface
You can administer and use MemVerge Memory Machine using the Command Line Interface (CLI) on any installed host.
MemVerge Memory Machine Administration
MemVerge Memory Machine can be installed and run using CLI commands.
Resetting a Host
Reset a host by removing all snapshot and log data and initializing the DAX devices. This erases the host's PMEM.

Overview and Installation
Getting started with MemVerge Memory Machine requries that you understand some background information about how persistent memory works. You can then install Memory Machine on a server and begin monitoring memory usage and capturing application snapshots.
Using the Memory Machine Management Center
Memory Machine Management Center (M3C) is a web UI application available on the host that is running the Memory Machine Management Service. You can view system resources and performance metrics; create and restore snapshots; schedule jobs; and more in M3C.
Using the Command Line Interface
You can administer and use MemVerge Memory Machine using the Command Line Interface (CLI) on any installed host.
- MemVerge Memory Machine Administration
  MemVerge Memory Machine can be installed and run using CLI commands.
  - Upgrading Memory Machine
    To upgrade Memory Machine, run the Memory Machine Package File on each host.
  - Uninstalling the MemVerge Memory Machine Data Service
    Uninstall the Memory Machine data service by running the Memory Machine uninstall script, uninstall.sh.
  - Upgrading Application Dependencies
    Upgrading dependency packages for snapshotted applications may render existing snapshots of that application unrestorable.
  - Understanding the Memory Machine Database
    Memory Machine Memory Machine Management Center (M3C) uses a database to store information about preferences, statistics, and configurations. You must choose a database system for M3C to use.
  - Understanding the Memory Machine Software License
    You must have a valid license to run Memory Machine. The license file is read at startup by the Distributed Persistent Memory Engine (DPME). Without a license, DPME defaults to running applications using only DRAM.
  - Running Memory Machine Services
    Memory Machine data services must be running to enable PMEM management, snapshot operations, and connection to the Memory Machine Management Center (M3C).
  - Using the Distributed Persistent Memory Engine
    The Distributed Persistent Memory Engine (DPME), mvmallocd, is a service that maps programmatic memory to PMEM. See oxy_ex-3/topics/a_mvmm_dpme_intro.html.
  - Using the Memory Machine Command Line Tool
    Memory Machine provides a command line tool, mvmcli, to show PMEM usage, set DRAM tier levels, manage snapshots, and manage data clusters.
  - Resetting a Host
    Reset a host by removing all snapshot and log data and initializing the DAX devices. This erases the host's PMEM.
  - Reporting Tiering Statistics
    Use the mvmcli command to view information about paging activity between PMEM and the DRAM performance tier for an application.
  - Viewing Logs
    Examine the Memory Machine log files to troubleshoot errors – for example, to determine why a license didn't load.
- Managing Application Memory
  To manage application memory with Memory Machine, you run the application on a data host in an environment with Transparent Memory Service (TMS) and Distributed Persistent Memory Engine (DPME).
- Using Snapshots in the Memory Machine CLI
  Use the mvmcli snapshot command from the CLI on a Memory Machine host to capture the state of a running process, then later restore the running process to the captured state.
- Troubleshooting
- Preparing Intel® Optane™ DC Persistent Memory PMEM
  Prepare PMEM for use by configuring the Intel Optane DC Direct Access (DAX) devices in AppDirect mode.
- Preparing to Run an Application
  Normally you run applications by using the mm wrapper script supplied with Memory Machine. See oxy_ex-3/topics/t_mvmm_running_an_application_with_mvmm.html. If you do not use the mm to run your application, you must set up the Memory Machine environment manually before running the application.
Working with Applications
MemVerge provides additional instructions for some popular applications supported by Memory Machine, either to assist with complex setup or to support additional functionality.
All Documentation
Links to documentation for all releases of MemVerge Memory Machine.

Resetting a Host

Reset a host by removing all snapshot and log data and initializing the DAX devices. This erases the host's PMEM.

About this task

Resetting a host erases all of the data on the host, including snapshots and snapshot logs.

Procedure

Stop DPME. See Stopping the Distributed Persistent Memory Engine.
Determine the file paths of the data and log directories. These are listed in the Memory Machine configuration directory file as DataDir and LogDir, respectively.
For example:
```
# cat /etc/memverge/mm.yml
InstallDir: /opt/memverge
DataDir: /var/memverge/data
LogDir: /var/log/memverge
```
Delete the snapshot data from the host.

Note: Memory Machine Standard Edition creates the data directory even though snapshots are not supported in Standard Edition.

Warning: Deleting the snapshot data directory renders all snapshots in PMEM irretrievable.

For example:
```
# rm -rf /var/memverge/data
```
Delete the log data from the system.
For example:
```
# rm -rf /var/log/memverge
```
Initialize the DAX devices. See Initializing Direct Access Devices.

Warning: Initializing the DAX devices erases all of the DAX devices assigned to Memory Machine.
Unpack the installer directory:
```
# MemoryMachine-release-OS.bin --noexec --keep
```
For example:
```
# cd /root
# ./MemoryMachine-20200911140634-rhel8.RETAIL.bin --noexec --keep
Creating directory rhel8
Verifying archive integrity... All good.
Uncompressing MemVerge Memory Machine  100%
#
```
The installer self-extracts a directory named after the OS. In the above example, the directory is rhel8. In that directory is a subdirectory called mvmm that contains the installation executables.
Recreate the data directory structure by running the configuration.sh script. For example:
```
# /rhel8/mvmm/configure.sh
```
The script recreates the data directory without reinstalling Memory Machine.