Exadata: Storage Cells IO performance metrics and IO distribution with DB servers

Yesterday day I was reading Uwe Hesse ‘s blog post  “Appliance? How #Exadata will impact your IT Organization” (you should read it too by the way :-) ) and then (I don’t know why) my mind switch back to my asmiostat utility and how it could be useful for the Exadata community.

Let me explain:

If you read my previous blog post “ASM Preferred Read: Collect performance metrics” you see that thanks to my asmiostat utility we are able to measure the IO distribution between ASM instances and failure groups. (ASM is not doing any IOs by the way that’s just a simple way to say:  The IOs generated by the databases linked to the ASM instance)

You see, that we are also able to measure the failure groups IO performance metrics (and their associated disks if needed) (see first post related to my asmiostat utility).

That said, now think about Exadata for which:

  • One ASM instance is running per DB server.
  • Each storage cell constitutes a separate failure group (in most common Exadata configuration) (see Expert Oracle Exadata Book for more details)

So, now come back to the first sentence of the explanation and simply change a few words for Exadata:

You see that thanks to my asmiostat utility we are able to measure the IO distribution between DB servers (ASM instances) and Storage cells (failure groups).

You see, that we are also able to measure the Storage cells (failure groups) IO performance metrics (and their associated Grid Disks (disks) if needed)

Remarks:  

  • In case your Exadata configuration does not follow this rule:  One  failure group per storage cell, just be aware that I will update my asmiostat utility so that it will be able to group by storage cells in any case (thanks to the IP located into the disks path). I’ll keep you posted once ready.
  • To get the asmiostat utility included into the real_time.pl script:  Click on the link, and then on the view source button and then copy/paste the source code. You can also download the script from this repository to avoid copy/paste (click on the link)
  • For a full description of my asmiostat utility see this post.

Update: The asmiostat utility is now able to deal with Exadata Cell’s IPs (see this post)

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