Dell PowerStore Importing External Storage to PowerStore Guide

Restrictions and limitations for SMB-only VDM file import

The following restrictions and limitations relate to a SMB-only VDM file migration from a VNX2 storage system to a PowerStore appliance:

• Only Unified VNX2 storage systems are supported as the source storage system in a VDM file-based import.
• Only VNX2 storage systems with operating environment (OE) version 8.1.x or later are supported.
• SMB1 must be enabled on the VNX2 source system. SMB2 and SMB3 are not supported in a VDM file-based import.
• Upgrading a PowerStore appliance when an import session is in progress is not supported.
• Creating an import session when an upgrade session is in progress is not supported.
• PowerStore supports a VDM import session with at most 500 file systems on the source VDM.
• The destination system must have enough available capacity to host the source resources to be imported.
  • PowerStore appliances use a different file system layout than Unified VNX2 storage systems. PowerStore appliances use UFS64 file systems while VNX2 storage systems use UFS32 file systems.
  • Import of deduplicate settings is not supported. During the import session, data is un-deduplicated and un-compressed.
  • A versioning file and fast clone are imported as a normal file. PowerStore appliances with operating system versions earlier than 3.0 do not support file-based import and File Level Retention (FLR). PowerStore appliances with operating system version 3.0 or later support file-based import and both FLR-E and FLR-C.
• Only uxfs-type file systems are imported from the VNX2 source VDM. Import of non-uxfs-type file systems or file systems that are mounted on a Nested Mount File System (NMFS) file system are not supported.
• A file system whose mount path contains more than two slashes is not supported. The destination system does not allow file systems with a name containing multiple slashes, for example, /root_vdm_1/a/c.
• Import of a file system that is a replication destination is not supported.
• Import of a checkpoint or checkpoint schedule is not supported.
• If the source replication file system is also the destination file system of a VDM import session, failing over the replication session (synchronous or asynchronous) is not allowed until the import is complete.
• Restrictions that are related to Quota import:
  • Import of group quota or inode quota settings is not supported. (The destination system does not support either.)
  • Import of a tree quota whose path contains single quotation marks is not supported. (A VNX2 system can create it but it cannot be queried or modified.)
• Limitations that are related to Host access:
  • After cutover, read access performance degrades until the related file is migrated.
  • After cutover, write access performance degrades until the VDM file migration is completed.
  • After cutover, a host cannot write data when the source file system is in the read-only mounted state.
  • (Does not apply to PowerStore appliances running operating system 3.0 or later) PowerStore appliances running operating system version 2.1.x or earlier do not support file-based import and FLR.
  • After cutover, a host cannot access data when the destination file mobility network cannot access the source file system, which includes the following cases:
    • The network between the source VDM file migration interface and the destination file mobility network is disconnected.
    • The source VDM is not in either the loaded or mounted state.
    • The user modifies the source export, which makes the destination system's file mobility network unable to access the source file system.
• Protocol restrictions:
  • Import of NFS settings, multiprotocol settings, and related settings is not supported. For example, LDAP, NIS, local password, group and netgroup files, mount options other than synchronous write, op locks, notify on write, and notify on access.
  • Import of FTP or SFTP (File Transfer Protocol), HTTP (Hyper Text Transfer Protocol), or CEPP (Common Event Publishing Protocol) is not supported.
• Cancel restrictions and limitations:
  • Only some configuration changes, such as the destination VDM's SMB shares, or local users along with data changes to the source file systems are rolled back to the source VDM.
• Configuration restrictions and limitations:
  • Import of NTP configuration is not supported.
  • Only enabled network interfaces on the source VDM are imported. Disabled network interfaces on the source VDM are not imported. (The destination system does not allow you to enable or disable network interfaces.)
  • File Level Retention (FLR) file systems can be imported on PowerStore appliances running operating system version 3.0 or later. However, PowerStore appliances with operating system versions earlier than 3.0 do not support file-based import and FLR.
  • Distributed Hierarchical Storage Management (DHSM)/(Cloud Tiering Appliance (CTA) might be configured on the source VNX2 for archiving inactive files to secondary storage. If DHSM/CTA is configured on the source VNX2 system and a VDM import to a PowerStore cluster is run, all the files on the associated file system are recalled from the secondary storage to the source VNX2.
• Only limited configuration changes to the source VDM and the destination NAS server are supported during import:
  • Shares
  • Local groups
  • Local users
  • Privileges
  • Home directory
  • Distributed File System (DFS) (only pre-existing DFS shares are synchronized during a cancel operation)
  Those are also the only configuration settings that are synchronized with the source if the migration is canceled.