Host Cannot Download Files From VMware vSphere Update Manager Patch Store

You may see following error when you scanning ESXi hosts by vCenter Update Manager. Host cannot download files from VMware vSphere Update Manager patch store. Check the network connectivity and firewall setup, and check esxupdate logs for details. You also see similar logs in /var/log/esxupdate.log. [Errno -2] Name or service not known The root cause … Read more

Transparent Page Sharing (TPS) is disabled by default in latest ESXi 5.5 patch

I just heared Transparent Page Sharing (TPS) is disabled by default in latest ESXi 5.5 patch. You may concern about that if your IT budget is tight since it means you need more memory for heavy virtual machines.

听说ESXi 5.5最新的patch里把TPS禁用了,专门研究了一下。觉得这对IT预算紧张的企业可能是个坏消息,因为这意味着你需要更多的内存应付大型虚拟机。

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Incompatible device backing specified for device ‘x’

It’s easy to find a solution for this particular problem. VMware has a KB for this error. Somehow it’s not my case. I don’t know what’s the exactly root cause but you can try vMotion the virtual machine to other host and give a try. Chinese Version 这个问题的解决方案很容易找到,VMware有一个知识库。但不知道为什么,我遇到的问题没法用此知识库解决。我通过vMotion虚拟机到其他ESXi 主机解决此问题,也不知道具体原因是什么。

Linux virtual machine hang on ESXi 5.5 host

English Version

Again something wrong on ESXi 5.5! Please don’t upgrade VMware Tools to 5.5 if you have Debian or Red Hat Linux virtual machine on your ESXi 5.5 hosts. There is a unsolved bug on vmmemctl drivers (balloon driver) of VMware Tools 5.5 can lead to Linux virtual machine hangs.

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The CPU has been disabled by the guest operating system

Few weeks ago, our database virtual machines got randomly failed. There was error message “The CPU has been disabled by the guest operating system. Power off or reset the virtual machine.” on VM events. I didn’t find any abnormal on vmkernel, hostd and vm logs. Finally our Linux team identified it’s a Linux kernel bug. Please refer to BUG at block/blk-core.c:NNNN! in blk_requeue_request or blk finish_request.

The bug only present on RedHat 6 on ESXi 5.5 with VMware Paravirtual SCSI drivers.

 

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Slow network performance on a virtual machine

It’s been a while since last technical post. I was pretty busy on preparation of holiday maintenance plan as well as few problems in virtual environment. There was one I’d like to share as it’s a sample to show how to ‘touch’ hardware layer from virtual layer. 🙂

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