3PAR Snap shots, VVSets and Hostgroups

[adamdb_uk]

Hi Guys,

just wanted to confirm my thinking on a couple of topics as I'm getting struggling to get a definitive response from HPE L3  (and now L2) tech support. I have a customer running 3.3.1 MU3 using hostsets for presentation of VV's over ISCSI. I know host sets are being used as SSMC clearly shows the volumes as being exported when looking at host set config.

Customer also has a number of VVSETS created which are used in conjunction with the 3PAR scheduler to take daily rolling storage level virtual snapshots which expire every 24h. Looking at vvset config screen it shows exported VV's as zero. All fine.

My understanding is that as hostsets are being used for presentation I should be able to make changes to the VVETS and or the createsv commands on the 3PAR scheduler and have zero impact on lun presentation to hosts.

However the L3 I've spoken to is insisting that if I want to modify or change a VVSet it will impact host presentation (even though none of the volumes are presented via this route).

They now have me doubting my own logic.

Just an example of some output below (edited to just include example of one group)

% showhostset
Id Name Members

2 VDI.Cluster
ESX11
ESX12
ESX17
ESX16
ESX13
ESX14
esx15
ESX18
ESX19

% showvlun -host set:VDI.Cluster
Active VLUNs
no vluns listed

VLUN Templates
Lun VVName HostName -Host_WWN/iSCSI_Name- Port Type
0 3PA01.VMFS.SCRATCH.06.TPVV set:VDI.Cluster ---------------- --- host set
6 3PA01.VMFS.VDI.1.TDVV set:VDI.Cluster ---------------- --- host set
7 3PA01.VMFS.VDI.2.TDVV set:VDI.Cluster ---------------- --- host set
8 3PA01.VMFS.VDI.3.TDVV set:VDI.Cluster ---------------- --- host set
9 3PA01.VMFS.VDI.4.TDVV set:VDI.Cluster ---------------- --- host set
10 3PA01.VMFS.VDI.5.TDVV set:VDI.Cluster ---------------- --- host set
------------------------------------------------------------------------------------------------
6 total


cli% showvvset
Id Name Members

5 VVSET2
3PA01.VMFS.VDI.1.TDVV
3PA01.VMFS.VDI.2.TDVV
3PA01.VMFS.VDI.3.TDVV
3PA01.VMFS.VDI.4.TDVV
3PA01.VMFS.VDI.5.TDVV

PSTO3PA01 cli% showvlun -t <edited>

Lun VVName HostName -Host_WWN/iSCSI_Name- Port Type
1 3PA01.VMFS.SCRATCH.06.TPVV ESX18 ---------------- --- host
2 3PA01.VMFS.VDI.1.TDVV ESX18 ---------------- --- host
3 3PA01.VMFS.VDI.2.TDVV ESX18 ---------------- --- host
4 3PA01.VMFS.VDI.3.TDVV ESX18 ---------------- --- host
5 3PA01.VMFS.VDI.4.TDVV ESX18 ---------------- --- host
11 3PA01.VMFS.VDI.5.TDVV ESX18 ---------------- --- host

cli% showvlun -v set:VVSET2
Active VLUNs
no vluns listed

VLUN Templates
no vluns listed


So the hostset VDI.Cluster is being used to present to ESXi.
We then only use the VVSet 'VVSET2' to perform snapshot operations from the schedulder
by running something like

createsv –exp 24h @count@-@d@-@b@-@H@@M@-@vvname@ set:VVSET2

which would perform a snap of all vols in VVSET2.

Can someone confirm my thinking is correct as I'm going around in circles with support!.?

I've also done this inside the 3PAR Sim and as far as I can tell if you are already using hostsets for presentation, come along later and add some VV's into a VVSET but that's all, just add them into a set and then use that to run your createsv commands from the scheduler then changing the VVSET or even deleting it should have zero impact as it's neve been used to present any VVs.

All I keep getting from support is 

"Removing a VV from the VVset it automatically gets unexported. If the customer adds VV to a VVset it automatically gets exported to the Hostset"

Very frustrating. Basically the vvset is only being used to create a list of VV's for the createsv command.. Nothing else!

thanks

[sbhat09]

Hi Adam,

Thanks for choosing HPE community forum. I am looking into this. I will get back to you.

Regards,

Srinivas

[Sheldon Smith · Accepted solution]

Hi Adam,

From what you show, you have only individual volumes presented to hostsets, and no VVsets presented. What the support person says is true only if the VVset is presented to one or more hosts or hostsets.
You are right in thinking changes to an unpresented VVset have no effect on VLUNs. VVsets have several use cases besides presenting the volumes to hosts.

[adamdb_uk]

Thanks Sheldon

                             I knew my logic seemed correct and just wanted a thumbs up from someone else to confirm it. Just a shame that the L2/L3 engineers I spoke to just trotted out the same line time after time even though i clearly pointed out my use case in detail. At least now I can see proceed with some level of confidence.

thanks.

Adam.