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08-19-08 Poor Man's FailOver for ESXi - Comments
During last week's chat the we discussed ESXi licensing and features. In the features portion of the discussion flakrat asked if it was possible to setup two ESXi servers with shared storage to be able to do a manual fail-over of a VM between the two servers. I was able to create this setup and confirm that it works. Read on for details.
The setup that I used to test was two PowerEdge R805 servers with ESXi Update 2 refresh installed on the hard drive. This was the currently available "free" ESXi installable from VMware's web site. To install I used the Dell Remote Access Card (DRAC) virtual media capability to boot from the ESXi ISO I downloaded. I selected the local hard disk as the location to install and let it complete. Once installed, I used the ESXi configuration to set the password, IP, gateway, and hostname for each server. I then installed the Virtual Infrastructure client on a windows server and used that to manage each of the R805 servers individually.
For shared storage I used a PowerVault MD3000i iSCSI storage array. I enabled the iSCSI software initiator on each server and discovered the the MD3000i. On server A, I created a VMFS partition and created a new VM called VMTest1. I installed Windows Server 2008 64-bit Enterprise Edition. After install completed I shutdown the VM on server A. I then went to server B and rescanned the storage adapters. It found the new VMFS partition on the shared iSCSI LUN. I created a VM using the same settings as I had on Server A including the same virutal hard disk file. I then boot the VM successfully.
The most interesting part of this test was to verify that the cluster file system of VMFS was still working without Virtual Center in the picture. So with the VM still running on Server B, I tried to start it on Server A - and I got an error message that the file was in use by another server. This was great because it showed that it would not be possible to run the VM at the same time on both servers.
We will chat more about this on today's chat - ESX and ESXi.
Todd
The setup that I used to test was two PowerEdge R805 servers with ESXi Update 2 refresh installed on the hard drive. This was the currently available "free" ESXi installable from VMware's web site. To install I used the Dell Remote Access Card (DRAC) virtual media capability to boot from the ESXi ISO I downloaded. I selected the local hard disk as the location to install and let it complete. Once installed, I used the ESXi configuration to set the password, IP, gateway, and hostname for each server. I then installed the Virtual Infrastructure client on a windows server and used that to manage each of the R805 servers individually.
For shared storage I used a PowerVault MD3000i iSCSI storage array. I enabled the iSCSI software initiator on each server and discovered the the MD3000i. On server A, I created a VMFS partition and created a new VM called VMTest1. I installed Windows Server 2008 64-bit Enterprise Edition. After install completed I shutdown the VM on server A. I then went to server B and rescanned the storage adapters. It found the new VMFS partition on the shared iSCSI LUN. I created a VM using the same settings as I had on Server A including the same virutal hard disk file. I then boot the VM successfully.
The most interesting part of this test was to verify that the cluster file system of VMFS was still working without Virtual Center in the picture. So with the VM still running on Server B, I tried to start it on Server A - and I got an error message that the file was in use by another server. This was great because it showed that it would not be possible to run the VM at the same time on both servers.
We will chat more about this on today's chat - ESX and ESXi.
Todd
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, Aug 19 2008, 1:49 PM EDT
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| Started By | Thread Subject | Replies | Last Post | |
|---|---|---|---|---|
| Haxim | Multiple ESXi Hosts accessing the same Virtual Disk | 2 | Sep 2 2008, 12:51 PM EDT by Haxim | |
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Thread started: Aug 28 2008, 1:05 PM EDT
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This was sort of our plan for our virtualization setup. I had a large 2TB datastore setup on my MD3000i and 3 ESXi hosts connected to it to store their virtual disks. We ran about 10 VMs for about a week in this configuration with no real issues. However, after talking with our MD3000i installation technician he strongly advised against this setup. Since ESXi has no real clustering capability on it's own, you have 3 independant hosts accessing the same virtual disk, which could lead to a few problems (I/O issues, possible data corruption). Has anyone else tried this? Is it really that risky if each ESXi host is running seperate VMs with seperate vmdk's being stored on the same shared virtual disk?
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Keyword tags:
cluster esxi md3000i
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