Administrator Guide

Table Of Contents
Multipath configuration
ME4 Series storage systems comply with the SCSI-3 standard for Asymmetrical Logical Unit Access (ALUA).
ALUA compliant storage systems will provide optimal and non-optimal path information to the host during device discovery, but
the operating system must be directed to use ALUA. You can use the following procedures to direct Windows and Linux systems
to use ALUA.
Use one of the following procedures to enable MPIO.
Enabling MPIO on Windows
1. Start Server Manager if it is not already running.
2. In the Manage menu, select Add Roles and Features.
3. In the Add Roles and Features Wizard, select Role-based or Feature Based Installation.
4. Click Next.
5. Select the server from the pool and then click Next.
6. Click Next again to go to the feature selection window.
7. Select the Multipath IO checkbox and then click Next.
8. Click Install.
9. When prompted, reboot the system.
When the reboot is complete, MPIO is ready to use.
Enabling MPIO on Linux
1. Run the following command to ensure that the multipath daemon is installed and set to start at run-time:
chkconfig multipathd on
2. Ensure the correct entries exist in the /etc/multipath.conf file on each OSS/MDS host. Create a separate device entry for
the ME4 Series storage system. The following table specifies four attributes that should be set. Run the following command
to obtain the exact vendor and product ID values:
multipath -v3
Attribute
Value
prio alua
failback immediate
vendor vendor-name
product product-ID
3. Run the following command to reload the multipath.conf file:
service multipathd reload
4. Run the following command to determine if the multipath daemon used ALUA to obtain the optimal/non-optimal paths:
multipath -v3 | grep alua
You should see output stating that ALUA was used to configure the path priorities. For example:
Oct 01 14:28:43 | sdb: prio = alua (controller setting) Oct 01 14:28:43 | sdb: alua prio
= 130
Best practices
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