What Factors Affect the Migration Speed?

The following table lists the factors that may affect the migration speed and duration.

OS	Factor	Description
None	CPU or memory usage	The migration occupies some memory and CPU resources of the source server. The usage varies depending on the source conditions. Before the migration, ensure that both the CPU usage and memory usage of the source server are not higher than 75%, and the available memory is at least 520 MB.
None	Network bandwidth	The network latency between the source and target servers must not be too high. The migration speed depends on the source bandwidth and the target bandwidth, whichever is smaller. For details about the network requirements, see How Do I Set Up a Secure Migration Network for Using SMS?
Windows	Disk fragments	SMS supports only block-level migration for Windows servers. During migration, the migration process identifies and migrates valid blocks. A large number of disk fragments will be generated on disks in daily use, which prolongs the migration duration.
Linux	Large files Too many small files	For a file-level Linux migration, the migration speed will be affected if There are files larger than 2 GB. There are a large number of small files, such as, those smaller than 20 KB.

The following table lists the factors that may affect the synchronization duration.

OS	Factor	Description
None	Too many new data on the source server Too many changed data on the source server	During an incremental synchronization, if a large amount of data is newly generated or changed on the source server, the synchronization takes a long time.
Windows	Too many file fragments	During a synchronization, if a large number of file fragments are generated on the source server, the synchronization takes a long time.
Linux	Large sparse files	During a synchronization, the system scans but does not migrate sparse files. If there are large sparse files on the source server, the synchronization takes a long time.