Infortrend SentinelRAID 170 320ML/sec SCSI-to-SCSI RAID Controller manual Dual Host Connection

SentinelRAID 170 Installation and Hardware Reference Manual

4.2.2 Dual Host Connection

In Figure 4-2two channels (CH0 and CH1) are configured as host channels and two channels (CH2 and CH3) are configured as drive channels. The firmware (FW) can be used to create LDs. These LDs must in turn be mapped to the host channels.

Figure 4-2: Dual Host Connection

♦Creating redundant host paths: If access to data is a critical requirement, redundant data paths to different LDs or logical volumes (LVs) can be created. To do this, logical units (LDs or LVs) are mapped to both the host channels (CH0 and CH1 in Figure 4-2). This will ensure that if one host computer fails, the second host computer will be able to access the logical units on that host computer.

NOTE: To create dual-redundant data paths on the host side, it is necessary for third-party failover software to be installed on the host computer(s).

♦Physically isolating one OS system from another: The multiple-host configuration can also be applied when the array is shared by two or more systems. Using each host channel for a host adapter on different host computers can physically isolate one OS system from another.

This configuration is applied when two systems cannot share the same SCSI bus as the access route to storage. Unless some file system "lock manager" is available, physical drives should be configured into different logical drives or logical volumes, and each logical unit should be mapped to IDs/LUNs on each host channel. In this way, each host computer will be accessing separate logical units.

4-4 SR 170 Topologies