Vsphere 6.5 Slot Size
When vSphere 6.5 was announced I was quite impressed about the features. Gathering more and more hands-on experience so far I am more than happy with it.
One of the new features that can have a real operational benefit hasn’t been documented so far that often (or at least I haven’t seen it anywhere).
Before vSphere 6.5 it was impossible to increase the VMDK size of a DISK that was larger than 2TB when the Virtual Machine was powered on. That was a fact that not many organizations were aware of it until they stumbled upon it.
VMKNOTENOUGHSLOTS 195887141 0xbad0025 ENFILE. 0xbad00f0 EINVAL Memory size exceeds. Hardware configurations supported by ESXi 6.5. Prior to vSphere 4.0 we used the number of vCPUs to determine the slotsize for CPU as well. But we do not use vCPUs anymore to determine the slot size for CPU. The slotsize for CPU is determined by the highest reservation or 256MHz (vSphere 4.x and prior) / 32MHz (vSphere 5) if no reservation is set.
Vsphere 6.5 Ha Slot Size
From an architectural point of view there shouldn’t be many use cases where such a large disk layout would be the best practice. But from an operational point of view for many of my customers this has been a bigger issue.
The good thing is: With vSphere 6.5 this is not the case anymore. Important: Hardware Version 13 (vHW 13) is not required for this to work – therefore just the vSphere platform and not the VM has to be upgraded.
Increasing a hard disk from 2.4 to 3TB will just work while the VM is powered on.
Voila. The disk can be used within with the fully size without any service interruption. Quite cool isn’t it?
Another quite useful enhancement within vSphere 6.5 is the fact that we can now see details about the hardware customization within the events. While in the pre vSphere 6.5 era we were only able to see that a configuration of the VM took place we see now more details about this VM configuration task.
Vsphere 6.5 Slot Size Chart
Just select reconfiguration event in Host & Clusters or VMs & Templates: VM -> Monitor -> Events
The first bigger vSphere 6.5 update must be around the corner. So I would recommend you to plan the upgrade. Check out my blog post about the general design considerations and tasks to be done before upgrading the vCenter.
The HA Deep Dive has been updated as part of the vSphere Clustering Deep Dive. The book (paper) can be bought through Amazon, or get the ebook version for free through Rubrik.
The VMware vSphere 6.7 Clustering Deep Dive is the long-awaited follow-up to best seller vSphere 5.1 Clustering Deep Dive and zooms in on the critical components of every VMware based infrastructure. It provides the knowledge and expertise needed to create a cloud infrastructure based on the solid foundation of vSphere HA, vSphere DRS, vSphere Storage DRS, Storage I/O Control and Network I/O Control. It explains the concepts and mechanisms behind these features that enables you to make well-educated decisions. The book contains a stretched cluster use case section that contains all necessary settings for creating a fully-functional stretched cluster and reviews all failure scenarios and their effect on the existing workload. This book takes you into the trenches of HA, DRS, Storage DRS, SIOC and NIOC and gives you the tools to understand and implement, e.g., HA admission control policies, DRS resource pools, Datastore Clusters, network resource pools, and resource allocation settings. Each section contains basic design principles that can be used for designing, implementing or improving VMware infrastructures. Combine this book with the vSphere 6.5 Host Resources Deep Dive book, and you have an in-depth and comprehensive set of books that deliver the information you need to design and administer vSphere in the enterprise. Often referred to in the virtual community as the vSphere Resource kit, the Host Resource Deep Dive zooms in on hardware resources such as CPU and Memory and covers how the vSphere 6.5 resource scheduler manages these. The Clustering Deep Dive builds on top of that and zooms in how a group of ESXi hosts work together and provide clustering services.