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I'm a software developer, but I understand the benefits of virtualization.

I asked our IT guy to buy a new HP Proliant with a Smart Array controller in RAID 5. We are a very small company, so I had originally suggested XenServer because it seems to be the free one that offers more features.

He said XenServer doesn't have the drivers for the P410 controller in RAID 5 (but it recognizes the disks if not in RAID configuration) and he would have to recompile the kernel... not sure how to take that information...

So he opted for the VMWare vSphere Hypervisor (the free one), but now says that vmware requires partitioning the storage according to the number of virtual servers to be installed in that host... I find it very puzzling and against the benefits of virtualization... so how true is that?

I found the vmware website very hard to navigate and find objective information, is there a better place to go?

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Not true.

The only 'official' information about ESX Partitioning is in the Install and Configure Guide

There is a configuration maximum of 256 virtual machines per volume.

Many recommendations exist regarding VMs (or virtual disks) per datastore, but they are usually based on the workload that is running on the VM.

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I think their site is purposefully bad, VMware wants you to buy ESX, Buy Support, Buy training buy more licenses... and so on. I think the real emphasis is that you will give them more money than their support is worth, and they'll dedicate a couple guys to you.

When I build out an esxi host I don't really partition out anything - ESXi sees the disks you have, and then you just put VMs in there and allocate space as you need it

You do have the option to create 'resource pools' but for smaller operations you probably don't need to worry about 'resource pools', as you can probably get away with out that feature.

So I don't know why he wants to 'partition the storage'.

As far as ESXi goes, its a decent hypervisor, and if the company you work for might see some expansion it could benifit from paid features in ESX (more cores per license, easier backups, better fault tolerance). Xen is ok too, haven't used it as much, but its just as easy as ESXi (and I think some things are a little easier since once you get into the OS you have a lot more tools at your hands than available in ESXi).

And yes, ESXi usually does have a wider array of driver support, although it has its problems too.

As far as an alternative what do you want to look at ? here is a how to article on creating VM's. I haven't seen much in the way of 'best practices' for partitioning storage, but for a small company I can't even imagine why you would want to 'partition' it. Just use it as you need it and buy more disk when you need more!

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probably best to keep editorial type of opinions out of answers – Reality Extractor Apr 3 '14 at 6:33

Prepartitioning is not required. You must check your hw in the VMware HCL Database: check your RAID controller and your disks. If you found your hw there you won need any drivers.

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What your "IT guy" is talking about is most likely that you have to take the raw disks and you have to create what VMware calls datastores. The datastores are containers that are formatted with the VMFS file system. VMs then reside within datastores.

Some "IT guys" create a datastore for each VM, but that approach is problematic because you can only have one datastore per LUN, so they then have to create a LUN for each VM as well. The admin overhead is crazy and there is little to no good reason for doing that.

Since each LUN can only have one datastore on it the datastore size usually equals the LUN size. Subsequently multiple VMs can reside within a single datastore.

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