Wu's Blog

Tag: storage

  • High KVAG and low VM performance when svmotion or clone

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    If you are using EMC VNX with ESXi 5.1, you may experience low performance when do storage vMotion or VM clone. This is a known issue on VNX, you have to disable VAAI feature to avoid this problem.

  • How to find which ESXi 5.1 host lock the VM

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    Sometimes VM may show unknown, invalid or orphan on vCenter Server, but it still running somewhere. Some technical support engineer may request reboot VM/ESXi host, or search on each host one by one. Declare: This article only apply to ESXi 5.1, I haven’t tested on other version. This is easiest way to find out which…

  • How to retrieve or set Path Selection Policy by vCLI

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    First of all, this article is nothing related to PowerCLI. 🙂 You probably know how to set Path Selection Policy (PSP) by vSphere Client, but how you can setup 100 LUNs manually? We have some script can make your life easy. How to retrieve LUN Path Selection Policy: esxcli storage nmp device list | egrep…

  • How to retrieve RDM information by PowerCLI

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    I worked on move RDM LUNs of Microsoft Cluster virtual machine from one iGroup to another. To make sure the moving safe, we should record RDM LUN information before migration. We had two VMs with almost 20 RDM LUNs, it’s pretty time consume to get the information manually, I used following script to retrieve information: $RMDinfo =…

  • Unknown status of Hardware Acceleration

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    When I read VMware documents, there is a cool feature Hardware Acceleration I found in storage book. That recall me an outage about one year ago, our NetApp filer was crashed due to motherboard problem, part of datastores was failed, we have to move virtual machine from the filer to other. We noticed the storage…

  • Unable to find new lun when you try to extend vmfs datastore

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    You probably see this rare problem: your storage team allocate new lun to esxi 5.0 host, lun is visible in add new storage screen, but invisible in extend datastore  screen. Add new storage screen: Increase datastore capacity:   That’s because the datastore, lun is connected to multiple esxi / esx host which have different version, please be…

  • ALUA Devices on ESXi 5.0

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    You may see the keyword ALUA frequently if you read VMware storage documents, so what’s the ALUA exactly is? How it reflects in ESXi 5.0? What’s the advantage of ALUA? I certainly have the questions, you? First of all, ALUA is short word of “Asymmetric Logic Unit Access”, you probably already knowJ, ALUA is a…

  • Move multiple datastores to a folder

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    We are moving virtual machine from old storage to new datastore today, there are a lot of old datastores need to be removed after migration, for saftey consideration, I move all old datastore to a folder and then do decommission process. There are more than 60 datastores, and vSphere client not allow move in one time. Here…

  • Extend ATS capability VMFS5 datastore maybe failed

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    A lot of storage support hardware acceleration, it is able to offload some storage operation from ESXi 5.x host to storage filer, the feature can significantly improve performance during cloning, vMotion, coping…etc. Different storage device may support different features of hardware acceleration, block device have block zero, full copy, hardware assisted locking, thin provisioning, NAS device…