vPivot

Scott Drummonds on Virtualization

MLC Flash Versus SLC Flash

1 Comment »

EMC’s recent announcement at EMC World of Project Lightning documents a program to increase the use of flash devices in enterprise storage. The project includes increased use of flash storage in EMC arrays, all-flash storage configurations, and support for Multi-layer Cell (MLC) flash. This last subject–MLC flash and its difference from SLC flash–piqued my curiosity.

Many years ago I studied electrical engineering. I was an awful at it. Analog was never my thing. I much prefer ones and zeroes. But I challenge myself to think about electronics once every blue moon. So I decided to delve into SLC and MLC flash technologies to understand how they differ and why we should care.  The content below summarizes my online research and the little bit I remember from school. If you can add, correct, or update this article I would be happy to have your comments.

Read the rest of this entry »

Virtual Storage Design: Application Consolidation

5 Comments »

Fixed recommendations for consolidation ratios are cancerous.  Whether we are talking about vCPUs per core, virtual machines per host, or VMDKs per LUN, there is no single number the represents the “right” ratio.  Accurate guidance requires workload characterization and fine tuning using vSphere’s performance counters.  Today I want to highlight one experiment that shows application choice impacting VMDK-to-LUN consolidation.  The inescapable conclusion is that sequential access data must be separated from random access files!

Read the rest of this entry »

Switch to our mobile site