When Security Key Lifecycle Manager is used as a key manager for the IBM SAN Volume Controller encryption, you can run into a deadlock situation if the key servers are running on encrypted storage provided by the IBM SAN Volume Controller. To avoid a deadlock situation, ensure that the IBM SAN Volume Controller is able to “talk” to an encryption server to get the unlock key after a power-on or restart scenario. Up to four SKLM servers are supported. 

Data encryption is protected by the Advanced Encryption Standard (AES) algorithm that uses a 256-bit symmetric encryption key in XTS mode, as defined in the Institute of Electrical and Electronics Engineers (IEEE) 1619-2007 standard as XTS-AES-256. That data encryption key is itself protected by a 256-bit AES key wrap when stored in non-volatile form. 

Because data security and encryption plays significant role in today’s storage environments, this book provides more details in Chapter 12, “Encryption” on page 629. 

## 2.2.17 iSCSI 

iSCSI is an alternative means of attaching hosts and external storage controllers to the IBM SAN Volume Controller. 

The iSCSI function is a software function that is provided by the IBM Spectrum Virtualize code, not hardware. In V7.7, IBM introduced software capabilities to allow the underlying virtualized storage to attach to IBM SAN Volume Controller using iSCSI protocol. 

iSCSI protocol allows the transport of SCSI commands and data over an Internet Protocol network (TCP/IP), which is based on IP routers and Ethernet switches. iSCSI is a block-level protocol that encapsulates SCSI commands. Therefore, it uses an existing IP network rather than Fibre Channel infrastructure. 

The major functions of iSCSI include encapsulation and the reliable delivery of CDB transactions between initiators and targets through the Internet Protocol network, especially over a potentially unreliable IP network. 

Every iSCSI node in the network must have an iSCSI name and address: 

GLYPH<SM590000> An iSCSI name  is a location-independent, permanent identifier for an iSCSI node. An iSCSI node has one iSCSI name, which stays constant for the life of the node. The terms initiator name  and target name  also refer to an iSCSI name. 

GLYPH<SM590000> An iSCSI address  specifies not only the iSCSI name of an iSCSI node, but a location of that node. The address consists of a host name or IP address, a TCP port number (for the target), and the iSCSI name of the node. An iSCSI node can have any number of addresses, which can change at any time, particularly if they are assigned by way of Dynamic Host Configuration Protocol (DHCP). An SVC node represents an iSCSI node and provides statically allocated IP addresses. 

## 2.2.18 IBM Real-time Compression 

IBM Real-time Compression is an attractive solution to address the increasing requirements for data storage, power, cooling, and floor space. When applied, IBM Real-time Compression can significantly save storage space so more data can be stored, and fewer storage enclosures are required to store a data set. 

