ISNS

Internet Storage Naming Service - RFC 4171

Contents 1 What is iSNS..? 2 How are iSNS and iSCSI related..? 3 What does the conceptual model of iSNS and iSCSI look like..? 4 How mature is iSNS today ..? 5 Do I need an iSNS control node client in order to run the iSNS server with non-control node clients..? 6 How can I change which node the iSNS server allows register as a control node client..? 7 What are the key OPTIONAL defined features for iSNS clients that are a requirements for iSCSI Active-Active Connection Recovery..? 8 What are the status of these features in other iSNS clients 9 When will iSNS be available from linux-iscsi.org..? 10 How can I setup my own iSNS Server.. ?

What is iSNS..?

The is a discovery and management protocol, sometimes called "DNS for SAN" that allows iSCSI and iFCP storage objects to be managed across multiple discovery domains and discovery domain sets.

How are iSNS and iSCSI related..?

iSCSI provides the storage, target portal group, and network portal object access to Initiator (client) and Target (server) nodes.

What does the conceptual model of iSNS and iSCSI look like..?

There are two implementation examples described within Section 4.1.2: iSCSI Object Model Diagrams, the latter is an advanced object model that is required for active-active high availability that is displayed here.

     +---------------------------------------------------------------+
     |                         IP Network                            |
     +-------------------+-----------------------+-------------------+
                         |                       |
                         |                       |
     +------------+------+------+---------+------+------+------------+
     |            | PORTAL 1    |         | PORTAL 2    |            |
     |            | -IP Addr 1  |         | -IP Addr 2  |            |
     |            | -TCP Port 1 |         | -TCP Port 2 |            |
     |            +-----+ +-----+         +-----+ +-----+            |
     |                  | |                     | |                  |
     |  +---------------+ +---------------------+ +---------------+  |
     |  +-------+ +----------------+ +-------------------+ +------+  |
     |          | |                | |                   | |         |
     |  +-------+ +-------+ +------+ +--------+ +--------+ +------+  |
     |  |                 | |                 | |                 |  |
     |  | STORAGE NODE 1  | | STORAGE NODE 2  | | STORAGE NODE 3  |  |
     |  |  -iSCSI Name 1  | |  -iSCSI Name 2  | |  -iSCSI Name 3  |  |
     |  |  -Alias: "disk1"| |  -Alias: "disk2"| |  -Alias: "disk3"|  |
     |  |  -Type: target  | |  -Type: target  | |  -Type: target  |  |
     |  |                 | |                 | |                 |  |
     |  +-----------------+ +-----------------+ +-----------------+  |
     |                                                               |
     |                         NETWORK ENTITY                        |
     |                    -Entity ID (FQDN): "dev1.example.com"      |
     |                    -Protocol: iSCSI                           |
     |                                                               |
     |                   Portal Group Object Table                   |
     |           Storage-Node Portal Portal-Group-Tag                |
     |                1         1           10                       |
     |                1         2         NULL (no access permitted) |
     |                2         1           20                       |
     |                2         2           20                       |
     |                3         1           30                       |
     |                3         2           10                       |
     |                                                               |
     +---------------------------------------------------------------+

How mature is iSNS today ..?

In order to perform administrative operations, an iSNS Control Node Client is required. Multiple iSNS control node clients exist, and the first open source control client is available from iSNS Control Node Client.

Do I need an iSNS control node client in order to run the iSNS server with non-control node clients..?

No, calling /etc/init.d/isnsserver start will start up the daemon and accept clients into the Default Discovery Domain.

How can I change which node the iSNS server allows register as a control node client..?

TODO

What are the key OPTIONAL defined features for iSNS clients that are a requirements for iSCSI Active-Active Connection Recovery..?

State Change Notification and Entity Status Interval.

What are the status of these features in other iSNS clients

This is moving along, and will start appearing in a larger number of environments as IP storage systems begins to takeoff.

When will iSNS be available from linux-iscsi.org..?

Currently, there are a few iSNS servers that support various levels of the RFC.

There is iSNS server code that is available from the svn. Please have a look at Linux iSNS Server Howto

An open source iSNS client and server containing State Change Notification and Entity Status Interval is expected to appear iSCSI Target systems begin to come online..

How can I setup my own iSNS Server.. ?

Please have a look at the Linux iSNS Server Howto