In an IP-SAN, LAN cables are used to connect hosts to storage systems. The cable port on the host is called a network interface card (NIC). In order to use an NIC, the iSCSI software must be installed ahead of time on the host. The cable port on the storage system is called a port (P) on a channel adapter (CHA) used for iSCSI connections.
A logical unit (LU) contained in a storage system is the target of input to, or output from, the host. You can divide an LU into multiple areas. Each area after the division is called a Dev. The Dev is equivalent to a partition. A route that connects a host and an LU is called a physical path, and a route that connects a host and a Dev is called a path. When an LU has been divided into multiple Devs, the number of paths set to the LU is equal to the number that is found by multiplying the number of physical paths by the number of Devs in the LU.
HDLM assigns an ID to a physical path and manages the paths on a physical-path basis. When you use HDLM, there is no need to consider the difference between a physical path and a path. Thus, hereafter both physical paths and paths might be called paths, without a distinction being made between the two. The ID that HDLM assigns for each physical path is called an AutoPATH_ID. Also, a path might be called a management target.
The following figure shows the configuration of an HDLM system using an IP-SAN.
The following table lists the HDLM system components when using an IP-SAN.
Components |
Description |
|---|---|
iSCSI software |
The driver software that contains the iSCSI initiator function. |
NIC |
A network interface card that serves as a cable port on a host. The NIC is referred to as the HBA in HDLM commands. Sometimes, it is also just simply called an HBA in this manual. |
IP-SAN |
A data transfer network that connects hosts and storage systems by using the iSCSI standard. |
CHA |
A channel adapter. |
P |
A port on a CHA. This serves as a cable port on a storage system. |
LU |
A logical unit (a logical volume defined on the storage system). This serves as the target of input or output operations from the host. |
Dev |
An area (partition) of a divided LU. |
Physical path |
A route that connects a host and an LU. |
Path |
A route that connects a host and a Dev. |
IP-SAN environments supported by HDLM
HDLM supports system configurations that use an IP-SAN in the following environments:
OS
Red Hat Enterprise Linux 7
Red Hat Enterprise Linux 8
Red Hat Enterprise Linux 9
SUSE LINUX Enterprise Server 12
SUSE LINUX Enterprise Server 15
Oracle Unbreakable Enterprise Kernel 7
Oracle Unbreakable Enterprise Kernel 8
iSCSI software
HDLM supports the following iSCSI initiators supplied with the OS.
For Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Oracle Unbreakable Enterprise Kernel 7, or Oracle Unbreakable Enterprise Kernel 8:
iscsi-initiator-utils
For SUSE LINUX Enterprise Server 12 or SUSE LINUX Enterprise Server 15:
open-iscsi
Storage system
IP-SAN can be used for the following storage systems: VSP One B20, VSP E series, VSP Gx00 models, and VSP Fx00 models.
Restrictions on using HDLM in an IP-SAN environment
The following restrictions apply when using HDLM in an IP-SAN environment:
The kdump function cannot be used.