Sometimes, you need your VMs to access a LUN directly over iSCSI. Direct access comes in handy when you, let’s say, run SAN/NAS-aware applications on vSphere VMs, or if you’re going to deploy some hardware-specific SCSI commands. Also, with direct access, physical-to-virtual conversion becomes possible without migrating a massive LUN to VMDK. Whatever. To enable your VMs to talk directly to LUN, you need a raw device mapping file. Recently, I created vSphere VMs with such disks. Well, apparently, this case is not unique, so I decided to share my experience in today’s article.

Typically, snapshots are used to return a virtual machine to its previous state in case of any errors during updates or configuration changes. Thus, they will save your system from unpredictable failures. But please, do not consider a snapshot as a backup and vice versa! Let’s be honest, snapshots are not backups. Each snapshot is associated with a certain set of indices (or a single index) to refer other blocks on the disk. If the corresponding storage goes down, you’ll lose all your data because you’ll be unable to restore everything from a snapshot. Based on this, be smart and do not rely on them and use the proper set of tools for backups. In other words, use a hammer for nails and screwdriver for screws.

  A couple of days ago, I decided to re-distribute VM resource shares. I, basically, wanted several VMs to get some more resource without compromising their latency. For that purpose, I played around with Storage I/O Control parameters a bit. And, you know, I decided to look at things more globally. Actually, here’s how I decided to take a deeper dive into I/O filtering. In today’s article, I’m going to tell you about the VMware vSphere APIs for I/O Filtering (VAIO) framework providing the direct access to the to the VM I/O stream. I shed light on how to enable those filters, how they work, and why you need them.

These days, hyperconverged solutions become increasingly prevalent in small- and medium-size datacenters. And, there’s no wonder: hyperconverged infrastructures (HCI) provide decent reliability and set of features typically associated with large datacenters… but for less money! So, why pay more?

Deduplication is a cool technique that some admins use when it comes to saving storage space. No wonder. By deduping, you can gain some extra storage even without deleting anything. Everyone seems to use it, but how does that thing, actually, work? In this article, I’ll look under dedupe hood to understand better its operating principles. Why one may need this? You see, you always can make the most of things once you understand how they work. I believe this principle to apply to almost everything! So, here’s why I examine such a common storage optimization technique as deduplication in this article. True, that’s up to you to dedupe or not. Today, I won’t discuss whether you need deduplication at all. Here’s a good article on this matter.

Being a sysadmin often means doing some boring stuff on a daily basis. Well, sure, you can use PowerCLI to save yourself the hassle. It’s a powerful tool that I believe any vSphere admin should master at some point. While PowerCLI provides you the ultimate freedom of IT infrastructure management, there’s still a workaround to automate some tasks even through GUI. For instance, you need, let’s say, to take a VM snapshot regularly, but you cannot write a script for that purpose yet. You still can automate that process and some other tasks with vCenter Server inbuilt task scheduler. No vCenter? No problems, you can schedule some processes on ESXi! The only thing is that you may be limited to the guest OS inbuilt scheduler capabilities. For more freedom, you need some PowerShell and PowerCLI skills. In today’s article, I look through some tasks that you can automate with vCenter and teach you how to schedule them.

A failed VM doesn’t have to mean lost data. Explore 5 methods to access and recover the data stored in a VMDK file, using both built-in VMware tools and third-party solutions.

  Sometimes, you badly need to provide your VMware VMs with more RAM or vCPUs without shutting them down. True, there’s a trick allowing you to do that – CPU Hot-Plug and Memory Hot-Add. In this article, I’ll discuss both these features and how to use them in different environments. Why do I write an article about Hot-Plug and Hot-Add in 2018 even though they were introduced back in ESXi 4.0? You see, there are very few in-depth studies of how Hot-Add and Hot-Plug work in different environments for some reasons. Sure, you can find a bunch of good articles about how you enable those features, why you need them, and when you may just want to leave them disabled (yes, they are disabled by default). There were some studies held for Windows guest OS family, but there is very few known about how Hot-Add/Hot-Plug work in Linux. Well, I hope to fill that gap with this article.

If you are new to VMware or just starting out in the tech, you may feel a bit confused about products naming. Well, at least I was. There are tons of products in the suite so many have a hard time grasping how all those things come together. For instance, it may be hard for a beginner to tell apart ESXi and vSphere. What should you do? Well, nothing special, you know. Google. Ask fellow admins. Look through forums. Read books. Well, my post is not here to bring you from the very beginning to finish. It’s rather a long process, and you need to pay your dues sometimes. Honestly, I got some knowledge only through fixing things that I had messed up. This post covers some questions that popped out in my head when I was only starting. And, my case is not unique. So, let’s start with VMware!