For a little while now we’ve been seeing RedHat Linux virtual machines performing poorly. Tasks would take considerably longer on the Linux VM’s then other Windows VM’s. After digging around I eventually found that RedHat has it’s own IO scheduler that runs in the background. On a physical box this wouldn’t be a big deal, but as a virtual machine everything is already being processed by VMware hypervisor. The fix, disable the IO Scheduler!
VMware has announced that VMware vSphere 6.5 has gone general available this week. Now installing VMware vCenter Server Appliance 6.5 (VCSA) is even easier as the requirement for the client integration plugin has been removed and now the VCSA appliance is delivered via an ISO image with an installation wizard that’s been broken up into two stages.
The VCSA 6.5 ISO offers two types of installation methods, CLI and GUI install – both availalbe for Windows, Mac and Linux machines. In this guide I’ll walk through the steps of installing VCSA 6.5 using the Windows GUI install.
In a recent VMware environment I was working in, we noticed that our incremental backups was taking a long time (like up to 7-8 hours) to complete. After digging around it was found that VMware actually has a feature built-in since version 4 called Change Block Tracking (CBT). CBT will track any blocks that were changed since the last backup and tag them and stores the information in a -CTK file. The obvious benefit is that now the third party software only backs up the changed block and not the entire VM each time, reducing the amount of data being backed thus speeding up backups and even lowers the CPU utilization on the VM host.
CBT is disabled by default though there are some backup tools that will enable it automatically or you can enable it manually which can easily be done following these steps:
VMware vSphere 6.5 has been released as general available and earlier this week I posted about Installing VMware vCenter Server Appliance 6.5 as a new install, this post will walk through upgrading an existing vCenter Server Appliance 6.0 to 6.5!
Similar to a fresh VCSA 6.5 install, the VCSA 6.5 upgrade is also broken up into two stages. The first stage is deploying a new vCenter Server Appliance and the second stage is copying data from the 6.0 VCSA to the newly deployed 6.5 VCSA.
If you don’t already know, VMware Update Manager (aka, VUM) is a tool which allows you to easily automate patching and upgrading VMware hosts as well as virtual machine hardware and VMware tools. It’s a wonderful tool and makes upgrading and patching so much easier and allows you to quickly see how compliant/up-to-date your environment is with the built in pie graph.
Recently we had some pretty serious array issues which corrupted the VUM database taking Update Manager down. Since we was going to have to rebuild Update Manager I opted to move from Windows Server 2008 to Windows Server 2012, in the steps below I’ll document step by step how to install VMware Update Manager 5.5 on Server 2012 and a separate database.
VMware just published KB 2136854 regarding a new bug found in ESXi 6.0 that causes virtual machine backups, which use Changed Block Tracking (CBT), to be inconsistent. VMware says the cause of the issue is this:
This issue occurs due to an issue with CBT in the disklib area, this causes the change tracking information of I/Os that occur during snapshot consolidation to be lost. The main backup payload data is never lost and it is always written to the backend device. However, the corresponding change tracking information entries which occur during the consolidation task are missed. Subsequent QueryDiskChangedAreas() calls do not include these missed blocks, hence a backup based on this CBT data is inconsistent.