I was browsing the VMTN community and noticed a great tip from my colleague Mostafa Khalil and I believe it is worth sharing with you. The original question was: “Does anybody have a list of which arrays support VAAI (or a certain subset of the VAAI features)?”. Mostafa updated the post a couple of days back with the following reponse [...]

I received a preliminary copy of a this report a couple of weeks ago, but since then nothing has changed. NetApp took the time to compare FC against, FCoE, iSCSI and NFS. Like most of us, probably, I still had the VI3 mindset and expected that FC would come out on top. Fact of the matter is that everything is [...]

I noticed a discussion on an internal mailinglist which mentioned the advanced setting “Disk.UseDeviceReset” as it is mentioned in the FC SAN guide. The myth that you need to set this setting to “0 “in order to allow for Disk.UseLunReset to function properly has been floating around too long. Lets discuss first what this options does. In short, when an [...]

Last week I noticed that one of the articles that I wrote in 2008 is still very popular. This article explains the various possible combinations of the advanced settings “EnableResignature” and “DisallowSnapshotLUN”. For those who don’t know what these options do in a VI3 environment; they allow you to access a volume which is marked as “unresolved” due to the [...]

We had a discussion internally about ESX/ESXi caching I/Os. In particular this discussion was around caching of writes  as a customer was concerned about consistency of their data. I fully understand that they are concerned and I know in the past some vendors were doing write caching however VMware does not do this for obvious reasons. Although performance is important [...]

It seems to be survey month…. Nevertheless this survey will take you a couple of minutes and is about Virtual Machine Storage and Snapshots. Most of our PMs are currently revising / updating and prioritizing the roadmap and real customer data and opinions are always welcome to define these. We would appreciate it if you could take 5 minutes of [...]

Disclaimer: Now, lets make this very clear. Don’t touch “useANO” unless you are specifically instructed to do so, this article is just for educational purposes. I had some issues in my lab with an ALUA array. (If you have no clue what ALUA is, read this post.) As you hopefully know with an ALUA array you typically have 4 paths. [...]