Configuring VMware VASA for EMC VNX

vSphere Storage APIs for Storage Awareness (VASA) are one of several VMware vSphere Storage APIs.  VASA, new in vSphere 5.0, provides vCenter with a way of interrogating storage array LUNs and associated datastores to gain visibility into the underlying hardware and configuration of the storage layer.  Storage capabilities, such as RAID level, thin or thick LUN provisioning, replication state, caching mechanisms, and auto-tiering are presented through VASA to vCenter (a unidirectional read operation by vCenter against the array).  With VASA, vCenter can identify which datastores possess … [Read more...]

Storage Basics – Part IX: Alternate IOPS Formula

It's been a long time since I published an article in my Storage Basics series - the series has been some of the top content on my site to date.  I sat for a beta version of the VMware Certified Advanced Professional - Desktop Design (VCAP-DTD) test today and was reminded by the test of a post I had in waiting about an alternate way to calculate IOPS (hint hint - memorize these formulas).  I have several more articles sitting in draft form, but a new job, crazy kids, home improvement projects, and a wife with chronic cerebral spinal fluid (CSF) leaks (it sounds bad - and it is - but look on … [Read more...]

Storage Basics – Part VII: Storage Alignment

At the risk of beating a dead horse, it's time to resurrect my Storage Basics series.  I've recently had some great feedback on the series and figured I should round out a few of the concepts before I wrap it up.  I want to cover a topic often discussed amongst virtualization professionals, but one I often find general practitioners and server admins not understanding: storage alignment.  Storage alignment, or the lack of alignment, is not a new issue and is not unique to VMware or virtualization in general.  However, the effects of misaligned storage can be more greatly felt in terms of … [Read more...]

Storage Basics – Part VI: Storage Workload Characterization

Most of what I covered in Storage Basics Parts 1 through 5 was at a very elementary level.  The math I used to do IOPS calculations, for example, is only true under very certain conditions.  RAID controllers implement caching and other techniques that skew the simple math that I provided.  I mentioned that the type of interface that you ought to use on your storage array should not be randomly chosen.  In fact, choosing the right array with the appropriate components and characteristics can only be done when you enlighten your decision with a characterization of workloads it will be … [Read more...]

Storage Basics – Part III: RAID

This is the third in a multi-part series on storage basics.  I've had some good feedback from folks in the SMB space saying that the first couple posts in this series have been beneficial, so we'll be sticking with some basic concepts for another post or two before we dive into some nitty-gritty details and practical applications of these concepts in a VMware environment.  In the second post of this series I introduced the concept of IOPS and explained how the physical characteristics of a hard disk drive determine the theoretical IOPS capability of a disk.  I then noted that you can aggregate … [Read more...]

Storage Basics – Part II: IOPS

In Part I of this series, I discussed the important of storage performance in a virtual environment (really any environment, virtual or not, where you want acceptable performance), and introduced some of the basic measures of a storage environment.  In Part II, we will look more closely at what may be the most important storage design consideration in a VMware server-consolidation enviornments, many SQL environments, and VDI environments to name a few: IOPS. If we stick with a single-disk-centric approach as we did in Part I, IOPS is quite simply a measure of how many read and write … [Read more...]