If you are upgrading to ESXi 5.1, there are some important facts that you should consider first. Upgrading involves many stages and processes that must be performed in a specific order. Many of these processes are one-way and do not provide a “back button.” If you do not use care and consideration in your upgrade plan, you could possibly lose important data and configuration, and potentially even lose contact with your servers. Understanding how to upgrade properly will ensure that you endure as little downtime as possible on each of your vSphere components. This three-part series covers several topics to consider when upgrading to ESXi 5.1, including:
- Why are you upgrading?
- What are you upgrading?
- What should you do to get ready?
- What is the correct upgrade process?
- What should you do after the upgrade is complete?
This series is not meant to be a complete guide, but it covers the most important topics and provides links to more detailed information on each key point.
Why Are You Upgrading?
If you are upgrading to vSphere 5.1, chances are good that it’s because vSphere 5.1 has features and benefits that you don’t have with your current version of VMware software. This paper is not long enough to even begin a discussion on all of the features and benefits that are available to you on vSphere 5.1 if it is installed properly. The bottom line is that you likely want to perform an installation or upgrade that will afford you the features and benefits that you want with as few headaches as possible.
What Are You Upgrading?
Whether you are upgrading from vSphere 4.x or vSphere 5.0, you need to understand the differences between what you have and what will be available after the upgrade. Of course, there are many new features and benefits available in vSphere 5.1 that were not part of earlier versions of vSphere; but you should also understand that some of what you may have become accustomed to using has been changed in the later versions of vSphere.
These changes may not be as dramatic if you are upgrading from vSphere 5.0 rather than from vSphere 4.x. One of the biggest differences that you will notice if you are upgrading from vSphere 4.x to ESXi 5.x is that ESX is no longer available. This means that the service console, a modified version of Red Hat Linux software, is no longer used. The service console has long been used for a management tool as well as a development environment.
The service console has been replaced by a management console that you connect to using a vmkernel port. Also, if you are concerned about where you will use your scripts, you have several options for development, including the vCLI, vSphere Management Assistant (VMA), and even a PowerShell-based PowerCLI. The end result is that you will have a smaller and more secure management platform and still have plenty of tools for development.
On the other hand, if you are upgrading from vSphere 5.0 to vSphere 5.1, then your biggest differences may seem small in comparison to upgrading from vSphere 4.x. This might be especially true if you have a relatively small network. Still, there are differences that you will have to consider in regard to user accounts and authentication and even with regard to setting a vCenter Administrator account. If this has piqued your interest, then keep reading!
What Should You Do to Get Ready?
Due to changes in the software architecture, not all of the configuration files, settings, and third-party tools are guaranteed to be migrated to ESXi 5.x. Because of this, VMware strongly recommends that you note all of your configuration modifications and customizations before performing the upgrade. As a best practice, you should backup any virtual machines (VMs) that are located on the local storage of your ESX/ESXi hosts.
In addition, when you are migrating to ESXi 5.1, you should ensure the following:
- Supported server platform.
- Supported 64-bit CPU with at least two cores
- Support for LAHF and SAHF CPU instructions
- NX/XD bit enabled for the CPU in the BIOS
- To support 64-bit Guest OS on VMs, Intel VT-x, or AMD RVI must be enabled
- Minimum 2GB of physical RAM; 8GB is recommended
- One or more Gigabit or 10Gbps Ethernet controllers
- SCSI disk or local RAID LUN (with unpartitioned space)
- Supported disk controllers include basic SCSI controllers, Adaptec Ultra-160 or Ultra-320, LSI Logic Fusion-MPT, or most NCR/Symbios SCSI. Supported RAID controllers include Dell PERC, Adaptec RAID, LSI Logic MegaRAID, HP Smart Array, or IBM ServeRAID controllers
- SATA, SAS, and SCSI are supported. IDE is not supported for disk. To use a SATA CD-ROM device on the host as a VM drive, you must use IDE emulation mode.
- Unified Extensible Firmware Interface hosts can boot from CD-ROM drives or USB media. Network booting or provisioning with VMware Auto Deploy requires legacy BIOS firmware.
Since that’s a long laundry list, you might need some help! One of the tools you can use to get ready is the vCenter Host Agent Pre-Upgrade Checker. You can run this tool from your vSphere Client to check whether the host is reachable, the disk space is sufficient, the network is functioning, the file system is intact, and required patches are applied. A successful check does not guarantee a successful upgrade, because the vCenter Host Agent Pre-Upgrade Checker only looks for known issues; but it’s a good start, whether you are planning on upgrading the hosts individually or using vCenter Update Manager. The vCenter Host Agent Pre-Upgrade Checker does not “fix” anything; instead, you must resolve the issues that it finds and then run the tool again to verify that they are fixed.
To enhance the performance of your host, VMware recommends that you also consider the following:
- CPU — Faster processors and larger caches improve performance. More cores will also enhance performance, but a VM will only obtain a maximum processing power equivalent to one physical core for each vCPU, so faster cores can make faster VMs.
- RAM — The more the better! You can have up to 2TB of RAM if your host supports it. You should consider using a minimum of 8GB of RAM on each host, so as to take full advantage of the new features in ESXi 5.1 and vSphere 5.1.
- Network — Place the management network and the VM network on separate physical cards. Consider using a card dedicated to a specific VM when necessary for maximum network performance.
- Disk — Do not place your VM files on the same physical disk as that of the ESXi host. Use physical disks that are easily large enough to hold all of the VM files and templates that you use. You will have better performance and fewer headaches.
Reproduced from Global Knowledge: Upgrading to ESXi 5.1 – Best Practices