vSphere Storage - ESXi 5.0 - Documentation - VMware
vSphere Storage - ESXi 5.0 - Documentation - VMware
vSphere Storage - ESXi 5.0 - Documentation - VMware
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
<strong>vSphere</strong> <strong>Storage</strong><br />
IBM System <strong>Storage</strong> DS4800 <strong>Storage</strong> Systems<br />
IBM System <strong>Storage</strong> DS4800 systems used to be called IBM FAStT. A number of storage array vendors<br />
(including LSI and <strong>Storage</strong>Tek) make SAN storage arrays that are compatible with the DS4800.<br />
For your host to work with IBM DS4800 and other compatible systems, make sure to set the multipathing policy<br />
on your host to Most Recently Used.<br />
Configuring the Hardware for SAN Failover with DS4800 <strong>Storage</strong> Servers<br />
This topic provides information on how to set up a highly available SAN failover configuration with an<br />
<strong>ESXi</strong> host and DS4800 storage.<br />
You must have the following hardware components:<br />
n Two FC HBAs, such as QLogic or Emulex, on each <strong>ESXi</strong> machine.<br />
n Two FC switches connecting the HBAs to the SAN (for example, FC switch 1 and FC switch 2).<br />
n Two SPs (for example, SP1 and SP2).<br />
Each SP must have at least two ports connected to the SAN.<br />
Use the following connection settings for the <strong>ESXi</strong> host, as shown in SAN Failover:<br />
n Connect each HBA on each <strong>ESXi</strong> machine to a separate switch. For example, connect HBA1 to FC switch<br />
1 and HBA2 to FC switch 2.<br />
Figure 5-1. SAN Failover<br />
Host 1 Host 2<br />
HBA1 HBA2 HBA3 HBA4<br />
FC switch 1<br />
SP1 SP2<br />
storage<br />
FC switch 2<br />
This configuration provides two paths from each HBA, so that each element of the connection can fail over to<br />
a redundant path. The order of the paths in this configuration provides HBA and switch failover without the<br />
need to trigger SP failover. The storage processor that the preferred paths are connected to must own the LUNs.<br />
In the preceding example configuration, SP1 owns them.<br />
NOTE The preceding example assumes that the switches are not connected through an Inter-Switch Link (ISL)<br />
in one fabric.<br />
Disabling Auto Volume Transfer<br />
To avoid the possibility of path thrashing, disable Auto Volume Transfer (AVT) on the SAN storage processors.<br />
If AVT is enabled, the two storage processors can alternately take ownership of the LUN in certain situations,<br />
resulting in performance degradation. AVT is also known as ADT (Auto Disk Transfer).<br />
To disable AVT, in the DS 4800 <strong>Storage</strong> Manager, for each port defined in each host group that contains HBAs<br />
for one or more <strong>ESXi</strong> hosts, set the host type to LNXCL or, in later versions, to <strong>VMware</strong>.<br />
You must reboot the hosts after you change the AVT configuration.<br />
46 <strong>VMware</strong>, Inc.