Developers Guide

Overview and requirements
5 Data Migration from Dell PS Series or PowerVault MD3 to Dell EMC SC Series Storage using Thin Import | 3041-BP-EM
2 Overview and requirements
The Thin Import process allows copying data from an external device and placing it onto an SC Series array.
This process works at a block level and uses synchronous replication to import the data. When the source
LUN is thin provisioned, all blocks on the source LUN are read and then written to the target volume on the
SC Series arrays with the exception of zeroed blocks, which are not actually committed to disk. The result is a
thin-provisioned volume on the SC Series array. When the source LUN is provisioned thick, the resulting
volume on the SC Series array is also thick. More detailed information on both the online and offline import
process is covered in section 5.
Note: The Thin Import process does not support importing data from 4K sector volumes.
There are two methods for importing data from an external device: online and offline.
Online importing creates a destination volume, maps it to the server, and then migrates the data to the
destination volume. I/O from the server continues to both the destination and source volumes during the
import. The online method can take longer than the offline method because I/O continues to the volume from
the server.
Note: Online import of a boot-from-SAN volume is not supported.
Offline importing migrates a volume from the source to the destination. It does not recreate the mapping on
the source volume.
Note: The Thin Import process is service-affecting in both offline and online mode. It is recommended to test
the Thin Import process in a non-production environment to establish an accurate timeframe of system
downtime. Both offline and online mode are discussed in detail in section 5.
Note: Importing from arrays other than PS Series or PowerVault MD3 storage must be performed by trained
professionals. Contact your sales representative to schedule an appointment with professional services.
2.1 Network requirements
Importing from a PS Series or an iSCSI-connected PowerVault MD3 array requires a high-bandwidth, low-
latency iSCSI network connection between the source array and the SC Series array. Both the source and
target arrays must reside in the same geographic location to minimize the risk of network latency.
Note: High latency or other network interruption during the import process will cause the data copy to fail and
restart from the beginning, regardless of the amount of data previously copied.
When importing from an iSCSI-connected PowerVault MD3 array, the MD3 must be connected to an
enterprise-class Ethernet switch. Using a low-cost switch could yield heavy Ethernet PAUSE frames, which
could result in an outage on the MD3 array.
2.1.1 Jumbo frames
The Thin Import process will work with SC Series, PS Series, and MD3 arrays configured to utilize Jumbo
frames. However, the source array, target SC Series array, and all network components (such as switches
and routers) must be set to the same maximum transmission unit (MTU) size.