To avoid performance issues, you must ensure that your SAN-attached storage systems and switches are correctly configured to work efficiently with symmetric virtualization.
The system does not require a license for its own control and expansion enclosures. However, a license is required for each enclosure of any external storage systems that are being virtualized. For example, if the system is made up of one control enclosure, one expansion enclosure, and one virtualized storage system that is itself made up of two enclosures, two licenses are required. The system can manage a combination of internal and external storage and represents all the detected storage as MDisks. For Lenovo Storage V3700 V2 and Lenovo Storage V3700 V2 XP systems, you can migrate data that is stored on external storage to internal storage, simplifying data and storage management. On Lenovo Storage V5030 and Lenovo Storage V5030F systems, a license is required for each enclosure of any external storage systems that are being virtualized. For example, if the system is made up of one control enclosure, one expansion enclosure, and one virtualized storage system that is itself made up of two enclosures, two licenses are required.
Virtualization provides many benefits over direct-attached or direct SAN-attached storage systems. However, virtualization is more susceptible to performance hot spots than direct-attached storage. Hot spots can cause I/O errors on your hosts and can potentially cause a loss of access to data.