Every now and then you see something which takes you completely by surprise. This is even better when it’s something new to Power systems and makes life a whole lot easier.
The HMC Enhanced+ GUI is getting a lot of stick, mostly from people who are used to the classic GUI and don’t want to change. I’ve persevered with the Enhanced+ GUI and now find that I rarely use the classic web interface any more.
The “Eureka!” moment came a couple of months ago when I wanted to create a new Shared Storage Pool for a customer on their Power 8 kit.
HMC V8R840 has SSP management built in to the Enhanced+ GUI and provides configuration and management capabilities for:
● VIOS instances in the SSP cluster
● Repository disk
● SAN volumes
● SSP tiers
● LUs contained within the SSP
All this is a far cry from the CLI and the limited SSP capabilities of the classic interface.
Creating your SSP
From the HMC Enhanced+ GUI select All Shared Storage Pool Clusters.
In the Actions drop down select Add.
The following shows screen shots from the HMC as we followed the Create SSP wizard.
Any fields with a red * denotes mandatory input. Note that you cannot overwrite the *.
Name your Cluster and your Shared Storage Pool. I normally give these the same name, after all you can only have one SSP per Cluster . . . . at the moment.
VIOS 2.2.4 provides tiering of storage in the SSP. I selected multiple tiers as I needed to split my workloads.
With a multi tier SSP we need to have a System Tier where there metadata for the entire SSP is stored. You can name this whatever you want but I stuck with naming it System.
I left the Threshold values at their defaults.
The HMC then scans the managed systems for all the VIOS instances which are eligible to be part of the cluster. As you can see the wizard has detected four VIOS.
You may notice on this screen that the SSP is showing as Mirrored. I actually don’t need any mirroring in my SSP so I can unset this in a later panel.
I selected all four of the VIOS instances and clicked Next>
SSPs require a repository disk. IBM recommend a 10GB drive but 1GB will suffice. As I prefer to stick to IBM guidelines to keep the support people of my back I’m prepared to sacrifice 9GB of SAN disk space.
What I really like about this is the wizard shows the Storage Label i.e. the name I gave to the volume on my Storwize system.
I select my 10GB repository disk and click Next>
Because I want a multi tiered SSP and I specified a tier called System I now need to assign a SAN volume to this tier. IBM guidelines for the System tier, used for metadata only, specify that a 300GB volume should be assigned.
Note that I unchecked the Mirroring tick box as I don’t require this tier of storage to be mirrored.
The wizard now displays a summary of my SSP showing the System tier, repository disk and the nodes (VIOS instances) which make up my SSP.
I’m happy with this so I click Finish.
At this point go away and have a well brewed cup of tea as the process of setting everything up may take over 10 minutes.
When the SSP build is complete you are returned to the All Shared Storage Pool Clusters window which shows a summary of the SSPs identified by your HMC.
Simply click the SSP name to take you into the detail of the SSP.
Now we can see the SSP details. From here we can manage tiers of storage, change the repository disk, if required, and manage our SSP nodes.
I needed another tier of storage so I selected the Add Tier button.
The wizard will display volumes (hdisks in VIOS) which are available to the SSP but currently unassigned to any SSP tiers.
Enter a name for your SSP tier and threshold values.
If you want to learn more about the thresholds click the Learn more link at the bottom of the window.
Again the Storage Label column shows the volume name as specified in the Storwize device. I selected the volumes I wanted to assign to the SSP tier and clicked OK.
After 30 seconds or so the SSP detail page is displayed again, this time showing the new tier I’ve just created.
You’ll notice that the System tier is specified as SYSTEM DEFAULT. This means that any new volumes created which do not specify a tier assignment will be created in the default tier. This is not what I want as the System tier is just for metadata.
I can select another tier and then choose Set Default from the Actions drop down menu.
That’s it, job done.
To create a volume to map to an LPAR simply go to the list of LPARs in HMC, click the LPAR name and select Virtual Storage from the navigation menu on the left hand side.
You can then create new volumes in the SSP and map this to the LPAR.
A bit more detail
I don’t want you to think that you only need to use this wizard to set up an SSP. There is some work to do beforehand:
● The repository, system and data volumes need to be created on the storage and then mapped to all of the VIOS instances you wish to be part of the SSP
● You will need to run the cfgdev command on each of the VIOS instances to detect the repository, system and data volumes mapped from the storage device
● The VIOS instances must be configured to resolve each other using a fully qualified domain name e.g. vios1.mydomain.local
I did eventually add a further 8 nodes (VIOS instances) to the SSP. This seemed to cause havoc and nodes were dropping out of the cluster. In the end I added each node one at a time and waited about 30 minutes between each add. This worked for me but you may see different results..
The Enhanced+ GUI
Yes it is different and requires you to think differently about how the HMC is used. The biggest drawback is that some of the commonly used functions are much slower than the classic GUI.
As I’m writing this I’m downloading HMC V8R850 as this has been released a few days ago. IBM are making a big fuss about significant performance improvements in V8R850. I’ll be upgrading a couple of HMCs to this new release soon so I’ll be reporting back on the improvements.
IBM have stated that they want VIOS to be no-touch. From an end user perspective they are very close. From a VIOS installation we still have to do some CLI stuff.
SSP tiers and PowerVC Gotcha
PowerVC 1.3 does not support SSP tiers, it does support SSPs.
I recently tried to capture an LPAR in PowerVC but it failed with error:
Capture of virtual machine MYLPAR_1 on host MYP8HOST_3 failed with exception: NV-DD01E5A Image volume creation failure for instance MYLPAR_1. Volume error: NV-62E5974 No detailed volume error message.
This baffled me for a while as my previous captures of other LPARs had worked fine. What I worked out was that PowerVC will only use the default tier of an SSP and my volumes for capture were not in the default tier. To work around this I went back to my HMC, in to the SSP and used Set Default to make the appropriate tier the default. Back in PowerVC I resubmitted my LPAR capture and everything worked as expected.