Network Attached Storage with iSCSI | Novell NetWare 6.5 Administrators Handbook

iSCSI is a new service offered with NetWare 6.5. SCSI , or Small Computer System Interface , is a standard for connecting storage devices to a computer. The SCSI standard requires a specialized 50-pin connector and ribbon cable between the SCSI controller and the hard drive. Given this limitation, SCSI devices typically have to be connected directly, and in close proximity to, the computer for which they are providing disk storage.

iSCSI is an exciting new standard that makes it possible to transmit SCSI communications over a network by encapsulating them in standard TCP/IP data packets. This lets you create a low-cost Storage Area Network (SAN) using regular high-speed network hardware, and avoid the considerable costs previously associated with fiber-based SAN architectures. A SAN allows you to consolidate network storage resources for multiple NetWare 6.5 servers.

iSCSI can be configured in a variety of ways, including a nondedicated system in which the iSCSI disk array is accessed through the normal network backbone; a dedicated system in which the iSCSI disk array is accessed through a separate network dedicated to serving the needs of the iSCSI environment; and a storage router option in which the dedicated iSCSI network uses specialized iSCSI router hardware to achieve even greater performance. You can evaluate your needs and choose the iSCSI solution that makes the most sense to you.

iSCSI Basics

There are two main components to the NetWare 6.5 iSCSI environment. The software necessary to use a NetWare 6.5 server is installed with the NetWare 6.5 operating system. You don't have to do any special installation routine in order to use iSCSI.

Initiator software is installed on each server that will use the shared iSCSI storage. The initiator software allows a NetWare 6.5 server or cluster to communicate with an iSCSI storage server or other iSCSI target over a normal TCP/IP network. At this time, the initiator software is only supported on NetWare 6.5.

Target software is installed on a NetWare server that will act as a disk controller for the shared iSCSI storage. A shared disk subsystem is attached directly to the NetWare 6.5 server running the target software. The target software allows external initiators to access the shared disk system.

Alternatively, a dedicated iSCSI router can be used for the target, in which case the NetWare 6.5 target software is unnecessary. The iSCSI router must comply with iSCSI Internet Draft Specification 20. A shared disk subsystem is attached directly to the iSCSI router according to the manufacturer's instructions.

Configuring the iSCSI Environment

Once you have determined the best iSCSI architecture for your needs, you are ready to configure the iSCSI environment. If you have chosen to use an iSCSI router as an iSCSI target, refer to the iSCSI storage router documentation for configuration details.

Configuring an iSCSI Target

There are three main steps to configuring NetWare 6.5 as an iSCSI target:

Create an iSCSI partition
Load iSCSI target software
Create storage pools and logical volumes on the target disk subsystem

You can use either NoRM or the console-based NSS Management utility (NSSMU) to create the iSCSI partition on your target subsystem. To create an iSCSI partition with NoRM, complete the following steps:

Launch iManager and open the Servers link in the left navigation frame. Click Launch NetWare Remote Manager.
Specify the server that will function as the iSCSI target and click OK. This will ensure that you are running NoRM for the correct server.
In NoRM, select Partition Disks in the left navigation frame.
In the right frame, locate the disk subsystem that will be used for iSCSI and click the Create link next to the free space associated with the device.
In Partition Type, select Novell iSCSI and click Create a New Partition.
Specify the size of the iSCSI partition and click CREATE.

With the iSCSI partition created, load the iSCSI target software on the server by entering the following command at the server console:
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 ton 
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You can unload the iSCSI target software by typing the following at the server console:
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 toff 
```
With the iSCSI target software loaded, use iManager to create NSS partitions, storage pools, and logical volumes on the iSCSI partition. The iSCSI partition will appear as a separate disk device to iSCSI initiators, so you still need to create an NSS partition on the iSCSI partition. The process for creating NSS partitions, pools, and volumes was discussed previously in this chapter.

Configuring iSCSI Initiators

To configure a NetWare 6.5 server as an iSCSI initiator, you must first load the initiator software on the server by entering the following at the server console:

ion

To configure the initiator software, use NoRM to complete the following steps:

Launch iManager and open the Servers link in the left navigation frame. Click Launch NetWare Remote Manager.
Specify the server that will function as the iSCSI target and click OK. This will ensure that you are running NoRM for the correct server.
Select the iSCSI Services link in the left navigation frame.
In the right frame, click Add Target.
Specify the IP address of the iSCSI target that is connected to the shared storage system and click Next. If the iSCSI disk subsystem is connected to a NetWare 6.5 server, the IP address is that of the NetWare server. If you are using an iSCSI router, the IP address is that of the iSCSI router.
Select the target(s) with which you want this initiator to establish an iSCSI session and click Next. Each target listed corresponds to an iSCSI partition you have created, so you can potentially have multiple targets associated with a single IP address.
At the server console of the initiator, use the List Devices command to have the server locate the new iSCSI storage device. The iSCSI subsystem will be listed along with other storage devices directly connected to the server.

With the target and initiator configured, you can access the iSCSI disk subsystem as if it were a directly attached resource on each NetWare 6.5 server configured as an initiator for that iSCSI device. Mapping drives , trustee rights, and directory and file attributes will all work identically to a directly connected storage device.