I want to test a certain configuration on a new server that has 6 disks, configured as 2 virtual disks in RAID 1 and RAID 10 configuration.


6 Total Disk Drives
2 x 250 GB RAID 1 Configuration
4 x 2TB RAID 10 Configuration

Currently I have the 250GB mirror set up as datastore1 and the 4TB raid array as datastore2.

I'd like to install a guest OSto datastore1 and allow it to access datastore2 as a filesystem which will show up in the Linux guest OS as a mount point. I don't plan on installing any guest OS'es to datastore2, I only want that disk space as raw storage.

Is there a way I can make this happen or was it incorrect to set up the disks as a datastore? I'm not sure if I need to make a virtual iSCSI target or something like that in order to do what I want.

I found this answer but am not sure if that is my solution or if there is some other way.

  • Do you just want the raw space or is are you trying to avoid formatting the RAID10 as VMFS? – Jed Daniels Mar 8 '12 at 1:44
  • I don't have a preference as to whether or not it is formatted as VMFS. If I get additional backup and recovery capability as VMFS then that's great. Currently the RAID 10 is set through the LSI RAID manager. If its easier to not format it as VMFS and set it up some other way, I'm open to that too. – drew010 Mar 8 '12 at 2:00

You can snapshot VMFS filesystems, allowing essentially instant roll-backs to a point in time image of the virtual disk. So that would be additional backup and recovery capability from within ESXi. However, snapshots create additional space usage, and can degrade performance over time. A great tool, depending on what you're trying to accomplish.

At this point, unless you have some need for raw scsi commands to the disks (probably not), leave it VMFS. Performance is comparable to raw. It will be easier to manage, and you can move virtual disks to other VMs, or add more virtual disks to the VMFS.

iSCSI is not needed for local server access. It allows storage commands to run over networks.

After you create your vm with the OS disk(s) on datastore1, you can add additional disks to the vm. Choose the datastore2 to house these virtual disks.

The .vmx file in the directory that the vm gets created in manages all the pointers to resources, where ever they really are. Play around with a dummy vm, adding resources, and then reading the vmx file to see what is going on.

  • Thanks for the response, this sounds exactly like what I am looking for. I'll try it out at work tomorrow and respond back. The 4TB array will probably be used only for storing MySQL data. – drew010 Mar 8 '12 at 3:09

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