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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.
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.
Listing Snapshots
List snapshots using the mvmcli snapshot list command.

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.

Listing Snapshots

List snapshots using the mvmcli snapshot list command.

Procedure

List snapshots that have been captured on the host:

$ mvmcli snapshot list -n app_name -T|-U|-R -r

$ mvmcli snapshot list -p|--pid pid
        -n|--application_name application_name
        -T|--snap-time
        -U|--used-pmem
        -R|--recoverable-pmem
        -r|--reverse

The pid and app_name parameters filter the listed snapshots:

pid: is the process ID, for listing snapshots of a single process.
app_name: is the application name, for listing snapshots of all instances of particular application.

If you do not specify a PID or an appliication name, all snapshots on the host are listed.

The remaining options sort the listed snapshots:

-T or --snap-time: causes the list to be sorted in order of time that the snapshot was taken, most recent first.
-U or --used-pmem: causes the list to be sorted in order of the amount of PMEM used by each snapshot, largest to smallest.
-R or --recoverable-pmem: causes the list to be sorted in order of the amount PMEM that can be recovered if the snapshot is deleted, largest to smallest.
-r: Reverses the order of a sort. For example, passing -T -r (or -Tr) lists snapshots oldest first rather than newest first.

For example:

$ mvmcli snapshot list -p 18074 -T
PID     User    Date Created      Application Status  PMEM Used  PMEM Freeable  Label
18074   root    2020-08-18 12:39  redis-serverP       4194304    4194304        redis_player_1_ca4a0982
18074   root    2020-08-17 12:39  redis-serverP       4033320    4033320        redis_player_1_40406881
18074   root    2020-08-16 12:40  redis-serverP       4009456    4009456        redis_player_1_21ecc005