Home
Using the Command Line Interface
You can administer and use MemVerge Memory Machine using the Command Line Interface (CLI) on any installed host.
Using Snapshots in the Memory Machine CLI
Use the mvmcli 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 state captured in the snapshot.
Using Snapshots in Memory Machine
Capturing a snapshot is almost instantaneous, requiring only that a small amount of metadata be saved to a storage device.
Capturing a Snapshot with CLI
Capture snapshots of a running application with the Memory Machine CLI utility, mvmcli.

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 Dashboard
You can view system resources and performance metrics, and create and restore snapshots in MemVerge Memory Machine using the Memory Machine Dashboard, a web UI application running on one of the installed hosts.
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.
- Using Snapshots in the Memory Machine CLI
  Use the mvmcli 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 state captured in the snapshot.
  - Using Snapshots in Memory Machine
    Capturing a snapshot is almost instantaneous, requiring only that a small amount of metadata be saved to a storage device.
    - Preparing a System for Snapshots
      Snapshots can be captured on a host on which Memory Machine is properly configured and the data service is running.
    - Snapshot Dependencies
      Capturing or restoring a snapshot with an established IP connection requires the iptables-utils package. MemVerge recommends installing iptables-utils on any data server on which ZeroIO Snapshot is used.
    - Capturing a Snapshot with CLI
      Capture snapshots of a running application with the Memory Machine CLI utility, mvmcli.
    - Listing Snapshots
      List snapshots using the mvmcli snapshot list command.
    - Restoring Snapshot Images
      Restore a snapshotted application image with the Memory Machine CLI utility, mvmcli.
    - Removing Snapshots
      Remove snapshots with the mvmcli snapshot rm command.
    - Copying Snapshots
      You can export and import snapshots – copy them to conventional storage and back into PMEM – using the mvmcli command. See oxy_ex-3/topics/t_mvmm_copying_a_snapshot_to_the_same_host.html. You can also clone an instance, creating an exact duplicate that can be run concurrently with the original process. See oxy_ex-3/topics/t_mvmm_cloning_an_instance.html.
- Troubleshooting
- Preparing Intel Optane DC PMEM
  Prepare PMEM for use by configuring the Intel Optane DC Direct Access (DAX) devices in AppDirect 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.

Capturing a Snapshot with CLI

Capture snapshots of a running application with the Memory Machine CLI utility, mvmcli.

About this task

For information about the CLI utility, see Using the Memory Machine Command Line Tool.

Warning: Changing an application dependency can render a snapshot unrestorable. See Upgrading Application Dependencies.

Procedure

Determine the PID of the application you want to snapshot:

$ mvmcli snapshot list
PID    User      Date Started              Command
-------------------------------------------------------------------
10918  root      Mon Sep 21 14:01:59 2020  redis-server --port 6380 
Snapshots:       Date Created              Status      Label
                 Mon Sep 21 14:11:11 2020  Incomplete  test1_97e38023
                 Mon Sep 21 14:30:39 2020  Incomplete  test3_73143fac
$

Capture the snapshot:

$ mvmcli snapshot create  -p pid_of_app  -l snapshot_name

where:

pid_of_app: is the PID of the application to be snapshotted.
snapshot_name: is a name you assign the snapshot image. A timestamp is appended to the name to create a unique snapshot label for the snapshot. (The timestamp format is YYYYMMDDHHMMSS.) You need this label to restore the snapshot image.

For example:

$ mvmcli snapshot create  -p 10918 -l test4
Successfully dumped process 18074 to /var/memverge/data/label/test4_740a02c2!
# mvmcli snapshot list
PID    User      Date Started              Command
-------------------------------------------------------------------
10918  root      Mon Sep 21 14:01:59 2020  redis-server --port 6380 
Snapshots:       Date Created              Status      Label
                 Mon Sep 21 14:11:11 2020  Incomplete  test1_97e38023
                 Mon Sep 21 14:30:39 2020  Incomplete  test3_73143fac
                 Mon Sep 21 14:30:57 2020  Incomplete  test4_740a02c2
$