Sunday, December 30, 2012

Performance History Issue in vCenter 5.1

Recently I was reading an internal posting and also found out through my colleague Josh Gray @jasper9, on Twitter that in vCenter 5.1 the Performance History is not retaining any information beyond 30 days. (which is only a month worth of data).

Now such performance data is crucial for getting the analysis done for so many things.

At present the issue is being investigated by VMware.

The issue is discussed here in KB 2042164.

@duncanyb has posted a blog here.

The alternate solution is put forward my @vcdxnz001 on this post here about using vCOPS Foundation.

Apart from it if you have a monthly backup of vCenter VM (complete VMDK) or the VC Database (either SQL or Oracle) then have the backup verified again and if possible make another copy of them. (individual monthly backup copies). So if you need for last one years performance history then you need 12 monthly back up copies of the vCenter Database. Depending on the requirements you can go and use the back up for any performance history retained in the database. Mainly if there is a new install of vCenter Server 5.1 then this should be for few months only as vSphere 5.1 released in October 2012.  It does affect to both instances of fresh install of vCenter Server and an upgrade of vCenter Server from an older versions to 5.1.

I suggest to use the option of "Subscribe to Document" on the KB page to get notification when the fix is released.

Sharing is caring. RT the Tweet if you can.

Wednesday, December 19, 2012

Storage Path Ranking in vSphere

Recently I was researching some storage related issues and found out this cool feature in @MostafaVMW's recent book on Storage Implementation on vSphere 5.0 about ranking your paths when you are using VMW_PSP_MRU with ALUA arrays or non-ALUA Active/Passive Arrays.

So by using the ranked paths you can (indirectly) actually configured preferred path without using the VMW_PSP_FIXED plugin.

As you can rank the paths in ALUA configuration, if one path is no longer valid then PSP fails back to a path which has a higher rank configured. In non-ALUA it goes by the path Group State which is Active and if not available then goes by Standby state. 

You can use the following command to setup the rank which goes in the way like "Higher the value and higher the rank for that path" (Default is 0 - Zero).

esxcli storage nmp psp generic pathconfig set -c "rank-" -p  

You can get the existing ranking for the path using the command:

esxcli storage nmp psp generic pathconfig get –p

Note: Where XX needs to be replaced by numeric value and path name should be provided depending on your requirement/s. Path names can be runtime path name or physical path name.

So to summarize if an AO path with highest rank fails , it will find the next path with highest rank and fails over to that path, but suppose there is no other AO path available with any ranking, then it will fail over to the next highest ranked path which is connected to a port in ANO state and eventually in standby state.

vSphere Client does not have the functionality at present to setup the ranking for the paths so you need to use esxcli command line only for now.

Hope you can use this feature in certain conditions where multipathing policies are not fully available but you can still benefit out of the existing setup using this feature.

I am just spreading the information for those who does not have access to the book. At the same time indeed suggesting to everyone to buy it and read it for further/deeper understanding of all the vSphere Storage related concepts.

Thanks and please share !!