darrylcauldwell.com On a journey around the datacenter and public cloud.

VMware Projects Fargo (VMFork) & Meteor

There was announced during VMworld a technology preview for Project Fargo (formerly VMFork) it is likely this will be launched with vSphere6. The aim of Fargo is to provides a fast, scalable differential clone of a running VM.  I see this as very similar to Redirect-on-Write (RoW) methodology used by NetApp snapshots where at the point of snap the existing blocks are frozen and any writes (creations/changes/deletions) are redirected to new blocks. However with Fargo rather than than a snapshot we are creating a Copy-on-Write(CoW) the difference being that with CoW the original data that is being written to is copied into a new file that is set aside for the snapshot before original data is overwritten. So before a write is allowed to a block, copy-on-write moves the original data block to the snapshot storage.

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NetApp FAS IOPS Theoretical Maximum & Workload Aggregate Load Balancing

To achieve good performance for a virtualized workload your Storage Area Network (SAN) should deliver high IOps with a predictable low latency. If you are using a good flash system where IOps (Input/Output Operations Per Second) effectively become an unlimited resource then latency will probably be your limiting factor.

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Jira Overview - Terminology Demystified

While I worked with Agile as a software tester when the concept first came out in 2002 shortly afterwards I joined a new company in a new role in Infrastructure, IT operations if you will. My recollection of Agile is that it was not a process at all; rather, it’s a set of principles summarized by the Agile Manifesto.

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How To Calculate Optimal TCP Window Size For Long Distance WAN Link

If you have a requirement to copy large amounts of data along way around the world you may find that despite your link being 60Mb/s if its 5,000 miles away you only can transfer files at much less like 10Mb/s. The cause of this is generally the TCP Window Size is optimized by OS and FTP clients by default to work on networks with less distance and less network round trip latency.

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vSphere Best Practice

I often get asked the question,  what is the best general configuration for private VMware hosting. Typically this is when an engineer or architect has been reading the multiple best practices and has become confused as much best practice advise is conditional. They just want to stand something up quickly with little detail on what the requirements are and then as solution gets used evolve the configuration based on the requirements which come through usage. Its certainly not ideal but does seem to happen a lot.

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