A customer is looking to analyse how effective FlashCache is currently, with a view to tweak the FlexShare configuration or possibly upgrade to FlashPools. Is there a guide into how to interrogate the NetApp stats to see the effectiveness of both FlexShare and FlashCache? It should also help to differentiate performance issues and guarantee service levels for critical systems.
If you read the tr-3832 ( http://media.netapp.com/documents/tr-3832.pdf ), and especially the Chapter 7 : "How Do You Monitor the Performance of Flash Cache?", you will probaly have a good idea how to achieve you customer goal.
In brief :
You can check the ext_cache_obj statistic by launching the following command :
stats show ext_cache_obj
Or you can launch a
stats show -p flexscale-access
to iterate the performance counter and see if everything is all right or not.
Thanks, this answers part of the customer's question. Do you know if there is a similar guide to cover FlexScale? The customer is analysing the FlashCache performance to ensure that FlexScale is performing correctly to prioritise the correct workloads and highlight when there is / isn’t a NetApp issue.
Another useful step is to have OnCommand track this for you. It provides some historical context to the use of Flash Cache rather than the real time tools or scripting it yourself