See host below that has no PowerPath installed. If planning to use Veritas; install it before PowerPath. Disable the setup script optional - the PowerPath setup script may interfere with other applications. Ensure sufficient stack size - the minimum required is 0x
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See host below that has no PowerPath installed. If planning to use Veritas; install it before PowerPath. Disable the setup script optional - the PowerPath setup script may interfere with other applications. Ensure sufficient stack size - the minimum required is 0x If you ever install another application that modifies this setting make sure it is at least 0x A stack size too small can cause a kernel panic and or stack overflow error messages.
Before removing devices from a server remove them from PowerPath with powermt remove. This way when the devices are presented back to the host they are brought in correctly for PowerPath to configure. When removing devices from PowerPath control it may complain about the devices being opened. Powerpath counts the number of open and close requests. If open requests exceeds close requests then the device can't be removed without first rebooting.
DMP and Powerpath both control devices, but powerpath is really solely controlling it. The ability to set both DMP and PP to control failover separately no longer exists on any of the currently supported software. DMP 3. The procedure below applies to old versions of Veritas. The pseudo devices are now recommend and automatically detected. Prepare a couple of scripts for read and write tests. Use the following PowerPath commands during these tests:.
Write failover test - the following script writes a bunch of 10M files. Run the script and via Navisphere trespass the LUN.
The writes will continue without any disruption in service. Read failover test - the following script reads the files created by the write script. Run the script and repeat the LUN trespass via exercise.
The reads will continue without any disruption in service. You can ignore these messages as PowerPath intercepts them and hides them from the application sending IO. Lets assume you had previously configured the host with a single zone to SP B and created a storage group with LUN access. You later add a zone for SP A and confirm the host has connectivity to both ports. Sometimes you need this procedure when replacing a failed HBA. PowerPath sits on top of the kernel and acts as a traffic cop.
However, it's configuration files are compiled at boot. Therefore, online commands do not always work and sometimes these files need to be recompiled and PowerPath needs to be reloaded.
The easiest and most effective way to do this is through a reboot. There aren't any other methods that are EMC approved besides remove the powermt. This hardly ever works. This is why EMC recommends a reboot.
If PowerPath gets duplicates pseudo entries caused by incorrect unmapping and remapping, first move ALL of the powermt. Register PowerPath on the host. Engineering Mode Cltrl Shift F12; enter password "messner". The words "Engineering Mode" appear on the tool bar. Right click the host storage group. Select properties, select host, and advanced.
Update host connectivity; select hosts tab, select host, right click, select Update Now. From Windows server command prompt verify boths paths are active.
EMC – Working with PowerPath
In this article, let us discuss how to use powermt command with practical examples. This is the most frequently used powermt command, which will display all the attached logical devices to the server. This is similar to 1, but displays whether hba is enabled or not, as shown in the last column of the output. You can change the mode of a specific HBA to either standby or active using this command. If a previously dead path is alive, it will be marked as alive, and if a previously alive path is dead, it will be marked as dead. For some reason, if you see the default owner and the current owner of a particular LUN is not the same storage processor, then execute the following command, which will make the current owner of the LUN same as the default owner.
15 EMC PowerPath Powermt Command Examples – Display, Check, Remove, Config, Restore