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XP Performance Advisor - Config Questions

Honored Contributor

XP Performance Advisor - Config Questions

Am ready to config Performance Advisor. And I have some questions:

1. Do I need to allocate a CMD LUN to each server that I need to monitor under PA? Or do I need to install only on one or two XP connected servers that have PA Clients on them (HostAgents)

2. Would the smallest LUN possible - 46 MB on the XP12K suffice as CMD LUN?

3. Can I concentrate my CMD LUNs on a particular array group? Or should I spread them out?

Hakuna Matata.
Sanjay Kumar Suri
Honored Contributor

Re: XP Performance Advisor - Config Questions

1. Only one CMD LUN in an XP is required. Performance advisor agent has to be installed on hosts collecting array performance data, LUN mappings etc.

2. Not sure on smallest LUN possible. In our case it is about 480 MB.

3. You can. Generally CMD devices are created on residual space. If you can spread it will be better.

A rigid mind is very sure, but often wrong. A flexible mind is generally unsure, but often right.
Honored Contributor

Re: XP Performance Advisor - Config Questions


Are you saying that say if I have 20 connected servers (heterogenous - UNIX/Windows/Linux) - that I only need one CMD LUN presented to one of these servers? I understand I need to have hostagents (PA Agents) installed on every node but I thought a CMD LUN needs to be presented on each and every XP connected machine.


Hakuna Matata.
Bill Rothanburg
Trusted Contributor

Re: XP Performance Advisor - Config Questions


With PA 2.0, you only need a command device on the host doing the data collection. The other servers do not need the command device for PA, but might need it for BC or CA.

You can use the smallest lun as there is no data actually stored on the command device.

My understanding is that the selection of the ldev to be used as a command device will have and affect on which ACP pair is associated with that command device.

I only create the command devices when I need them and pick them out of a pool of CVS volumes that we have set aside for quorum disks.

Also, we had some performance problems collecting the data off of our XP1024 (85TB of storage). If you expierence problems collecting the data in a timely manner, you may need to upgrade your PA and the host agents.


Honored Contributor

Re: XP Performance Advisor - Config Questions


You only need one CMD LUN (typically referred to as a Command Device) to collect data for PA. The Cmd Dev is used as a proxy from the PA wkstn to gather the data in-band from the frame. The data path for the PA data is:

XP->Cmd Dev->SAN->Host with PA host agent-> IP network->PA wkstn.

As stated in prior reply, you only need a small LUN, typically a CVS volume that is 35MB in size (smallest allowed).

Once you have PA up and running, it gathers data for ALL the LDEV's / LUNs on the array, not just the hosts with a host agent. HOWEVER, host agents are the means that the PA wkstn uses to correlate an LDEV to a host. Without a host agent, you would will have to break out your spreadsheet or XPDT report and manually correlate the LDEVs to your hosts. This can be very tedious and time consuming on a large frame.

Hope this answers your question

"In Vino Veritas"