User guide

101MAXDATA SR1202 M1 – StorView
®
RAID User Guide
12 Failover, Performance and Additional Functions
How StorView Server Failover Works
The failover feature of the StorView RAID Module must have one of the following setups.
If you are using the host-based version of StorView, two or more host servers must be directly
connected to the SR1202 RAID Storage Solution enclosure and each host must have a copy of StorView
installed with a Global Access license. If you are using the embedded version of StorView, you must
have dual controllers installed (duplex topology) each with embedded StorView installed.
At startup, each StorView server will create a device list of all the attached storage systems. It then
sends the list out on the network as a device list packet. The other StorView servers on the network
will then respond with their device list packets. Since the StorView servers are attached to the same
storage solution, they will have the same or similar devices in their device list packet. The identical
devices in each device list packet will be flagged. After analysis, the StorView server with the lowest
serial number or address will take control of those devices. The other StorView Server will indicate
on its interface that another StorView server is monitoring the storage solution.
During normal operations, the StorView server(s) send “check-in” packets every 10 seconds. If three
consecutive check-in packets for a specific StorView Server are not received, its devices are flagged
and the StorView server attached to that storage solution with the lowest serial number or address
will take control of those devices.
StorView Performance Optimization
There are some parameters that can be adjusted on the host HBA and operating system to increase
the performance of StorView. They are HBA Execution Throttle setting and the operating system‘s
Scatter/Gather registry setting.
Execution Throttle
To improve general I/O performance by allowing more commands on the fibre bus or the SCSI bus,
we recommend changing your host bus adapter’s execution throttle parameter to 256. Refer to your
host HBA documentation for more information.
Scatter/Gather
(Microsoft Windows Only)
To increase general I/O performance by allowing larger data transfers we recommend editing the
“MaximumSGList” parameter in the registry. The recommended hexadecimal value is “ff”. The path
is:
HKEY_LOCAL_MACHINE/System/CurrentControlSet/Services/<name of HBA driver>/
Parameters/Device/
Refer to your Microsoft Windows operating system documentation for more information on editing
the registry and your host HBA adapter documentation.