13 Replies Latest reply: Oct 29, 2014 7:39 AM by rfenton RSS

    CS500 24TB - Cache Size

    Roland Kudelic Wayfarer

      Hi there

       

      Which Cache Size for a CS500 with 24TB Raw is recommended? 10% of actual Data Size? Means for me, if used 12TB Data, Cache Size should be 1.2 TB.

       

      Kind regards

      Roland

        • Re: CS500 24TB - Cache Size
          Nick Dyer Navigator

          I have a very rough sizing for cache and it usually comes down to "buy the biggest you can afford"

           

          Technically I always want 10% usable cache capacity to your uncompressed data set so you've got your sizing correct - however as you add more workloads to the system over time you may see cache be overutilised depending on what said workload is. For me, this is where Infosight is brilliant as you (and we) can visualise this and plan accordingly for it.

           

          If the majority of your workload is something like SQL Server then you'll absolutely need more than 10% cache allocation as from my experience databases (especially batch jobs) will require lots more working set than your average application. Here I would recommend a minimum of 2.4TB and maybe even as high as 3.2TB.

           

          If it's mostly standard VM workloads then 1.2TB is perfectly fine.

           

          Us Systems Engineers do have access to workload specific cache sizing tools based on Infosight data analytics so don't hesitate to chat to your SE for some more exact sizing figures.

          • Re: CS500 24TB - Cache Size
            Paul Frisoli Adventurer

            Good morning Roland

             

            I agree with Nick and I also use a performance analysis tool (Cloudoscope) to help capture and clarify an end-users workloads (i.e.: IO, Read/Writes, etc...). I also believe in adding in a proportional amount of growth overhead to support new found or unexpected growth. In most cases, applications such as mail, databases, etc will certainly demand the need for more cache versus flat file consumption. I hope this helps. Paul