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Hi Eriks,

Specific to you questions about why you cannot achieve 200MB/s, there are some specific physics/physical reasons why this is the case.  Firstly, your file copy is a completely different IO operation - it's performed at larger block size requests and 100% sequential in operation benefiting from file cache and/or storage controller cache along with NTFS read-ahead prediction.  

In a Caché SQL query, Caché (or IRIS) will do 8KB block reads and presumably random in nature as well depending on the query and the data/global structure, so any caching will be mostly limited to whatever you have defined for database cache (global buffers) in the Caché instance.  Since this is 5.0.21, I wouldn't expect your installation to have hundreds of GBs of global buffers (and I would not recommend that on 5.0.21 either), so you are at the mercy of disk latency of a single process doing random 8KB reads and not total throughput you see in a file copy operation.  

So, based on ~20MB/sec you are seeing, this indicates you are getting about 2500 8KB IOPS or .4ms single process storage latency - this is actually very good performance for a single process.  As you add more jobs in parallel you start approaching other limits in the IO chain such as SCSI queue depths at the VM layer, at the VMware ESXi layer, etc... and its more a IO operation limitation than a throughput (MB/s) limitation.

I hope this helps explain the situation you are seeing, and expected behavior because the ~20MB/s you see is just a factor of storage latency for a single process (.4ms) so that's a max IOPS per second (~2500) * 8KB IO size = ~20MB/sec

Kind regards,

Mark B-

They used to be available on our website, but have since been removed since the results where from 3 years ago.  The summary results from 2015 and 2017 have been included in graph-1 above in this new report for comparison.  Thanks.

Correct.  Gold 6252 series (aka "Cascade Lake") supports both DCPMM and DRAM.  However, keep in mind that when using DCPMM you need to have DRAM and should adhere to at least a 8:1 ratio of DCPMM:DRAM.

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