Overview of the file import process

To understand the migration procedure, review the following processes:

Prepare the Source VDM for Import:
- Create a source import network interface.
- Clients connect to the source VDM through NFSv3, SMB1/SMB3 sharing protocol of the choice.
- Add a migration network interface for IMT:
  - Create a migration interface.
  - Attach the interface to migration VDM.
```
nas_server -vdm vdm_fro2 -attach nas_migration_vdmfro2
```
- When importing a CIFS server:
  - Interface must have a different DNS subdomain than the CIFS server.
  - Add the interface to the CIFS server:
```
server_cifs vdm_fro2 –addcompname=vnx2compnamefro,domain=windows.emcfr,interface=nas_migration_vdmfro2,dns=migration.windows.emc-fr
```
  - Update parameters essential for CIFS import
    - acl.mappingErrorAction
  - Defines the rules for unknown mapping between SID, UID, and GID on ACL settings.
    - acl.extacl
  - This parameter is a bit list which enables special capabilities around ACL management.
  - Allows migrating of UNIX ownership necessary for preserving Quota.
    - smb1.disabled
  - This parameter must be set to 0 to ensure smb1 is enabled
    - Review mandatory parameter values:
      - server_param server_3 -f cifs -info
      - acl.mappingErrorAction
      - Server_param server_3 -f cifs -info acl.extacl
      - Server_param server_3 -f cifs -info smb1.disabled
    - Set new values
      - server_param server_3 -f cifs -modify
      - acl.mappingErrorAction -value 11
      - server_param server_3 -f cifs -modify acl.extacl -value 28
      - server_param server_3 -f cifs -modify smb1.disabled -value 0
  - Ensure that local groups are enabled, and set two options:
    - Set the local Administrator password using Computer Management.
    - Create a local admin user using Computer Management.
      - Must be added to theo Administrators group
  - Ensure that time is synchronized with destination:
    - Within 5 seconds
    - Recommend using NTP
  - Ensure that all interfaces used by the VDM are attached to the VDM. Use the following command to attach interfaces to the source VDM:
```
nas_server -vdm <vdm name> -attach <interface name>
```
Create a File Migration Network
- Target node cluster VDM should have an interface on data protection network, this is used by target node to establish control path to the source node (using SSH).
Add the Remote System for Import Connection:
- Establish a file import interface connection to the source eNAS (Control Station management interface) from PowerMax over SSH.
- The system is validated, and source VDMs are discovered, including their configurations like file systems and network interfaces.
- Pre-checks identify the import capability for each VDM on the source system.
Create a File Import Session:
- Specify all the import options and validate user settings and the source VDM.
- A maximum of ten active import sessions are allowed.

Start the File Import Session:

NOTE: The basic configuration of the source VDM must not change since an import session is created.

The import session begins – Destination NAS server, destination file network, and destination file systems are created. In the case of an NFS import, un-exported file systems are exported.
Initial (baseline) data copy is initiated. Stable data and directory structure is pulled to the destination.

Import of the configuration from the source VDM to the destination NAS server occurs. The configuration includes:

Production network interfaces
Static routes
DNS
SMB server
SMB shares
NFS server
NFS exports
NIS
LDAP
Local files
Effective naming service

Quotas

NOTE: The session state is shown as Ready_to_Cutover when the import of the configuration completes. If the file system on the destination system is low on space (reaches 95% of capacity) during import, import of the source file system fails. In this case you can either ensure that enough space is available and run Resume or Cancel the import session.

Cut over the import session :

Production interfaces are disabled on the source side and enabled on the destination side.
For SMB import, the Active Directory configuration is imported and the switch over is disruptive.
For NFS import, NLM locks are reclaimed for transparent switch over and clients may experience a 30-90 s downtime.
An incremental data copy begins – Live import and re-synchronization of data from the source to the destination occurs.

NOTE: Clientsare connected to the destination, and the source is updated with modifications from the destination. The source is authoritative. File Creation/Write is done first on the source. When re-synchronization occurs on a file, it is marked up to date and further reads are done from the destination. For a file or directory that is not synchronized yet, all operations are forwarded to the source. During synchronization, file read can be done on the destination (partial read) for imported data that is already committed on this file. Some configuration changes on the destination during an import are pushed back to the source in a rollback. During an import, snapshots/backups can be created on the source VDM. Replication from the source is still active, and user quota management is still active on the source VDM. When all files are synchronized, the status of the import session is shown as Ready_to_Commit.

Commit the import session:
- Protocol data connections to the source terminate and synchronizing modifications stop.
- The destination import interface is deleted, and cleanup of the source system occurs.
- The final state is shown as Completed.

In addition, the following actions are available during the import procedure:

Pause import – Pause can be performed when the import processing state is Copy In Progress during session create or cutover operations.

NOTE: When a user tries to pause an import session when an incremental copy is about to complete, the session can be transitioned automatically from the Paused state to the Ready_to_Commit state without the user having to resume the import session. The Ready_to_Commit state is equivalent to the Paused state in terms of the load on the source system.

Resume import – Resume can be performed when the import processing state is Paused.
Cancel import – Cancel is allowed at any state of the file import session except Completed, Failed, Cancelling, and Cancelled.

Production interfaces are disabled on the destination side and enabled on the source side. Cancel is disruptive for NFS and SMB clients. Some changes to the configuration will be synchronized from the destination to the source. The source system is cleaned up, and the destination NAS server is deleted. Cancelled is a terminal state. Cancel can be forced if the source stops responding.