ESXi Host drives - all VMs on SAN

The drives the hypervisor runs on can be low-end since performance isn't an issue, UNLESS you have the datastore on the same local drives. So, if you separate out your datastore from the hypervisor, your disks can be SATA, RAID1. Since we're talking about ESXi, I would actually consider installing it on a SD Card (USB).

Hope that answers your question...let me know if not.

Regards,
~coolsport00

It does. Out of interest, is there some kind of VMware document stating this?

Save you expensive SAN Storage and install ESXi on a USB Flash Drive or SD card, it only uses the Disks to startup and then it runs from memory!

Here is the VMware KB on installing 4.1 on USB/SD:
http://kb.vmware.com/kb/1020655

(you can even remove the USB/SD card, when it's booted and it still runs!)

Not really. It's more of a 'storage' knowledge thing, and determining your org SLA for performance for a given server and/or app and being inline with server or app sys req's. For example, if you plan on virtualing SQL, you want a real high performance SQL VM, right? So, you would mirror volumes on the VM like you would a phys box (DBs on a volume, logs on another), but since you want high performance, you would create a datastore in a RAID1+0 and place both the DB/Log volumes on that (the SQL VM sys volume, C:, could be a RAID5 or RAID1). Now, in that scenario, you would have a few datastores of different RAID types obviously. But, that is just an example. Virtualization doesn't change how you configure apps/servers....you mirror what you would do on a phys box, but it takes planning of datastores (separating DB VMs...like, placing on diffferent RAID Group LUNs/datastores, etc.).

VMware provides some 'best practices' whitepapers, but nothing saying "hey, this is how we recommend you install your ESXi hypervisor". They just give what is supported, as referenced on pg. 25 of the ESXi install guide:
http://www.vmware.com/pdf/vsphere4/r41/vsp_41_esxi_i_vc_setup_guide.pdf; may benefit looking through these as well:
http://www.vmware.com/pdf/Perf_Best_Practices_vSphere4.0.pdf
http://www.vmware.com/technical-resources/virtual-storage/best-practices.html

When VMware decided what drives were supported they must have written some kind of supporting information to show how and why it will work on slow hardware.

Sorry to delay this but I must provide some kind of documentation to show that this will work just as well as faster disk (don't get me wrong, I understand this) however if I can't prove it, my company heads will not accept that it would not be a hinderance to the Host.

It will work on slow disks, but performance will be very slow.

Characterize storage performance and correct: Storage Performance Analysis and Monitoring

Sorry hanccocka, we are still referring to host only disk.

LUNs from a SAN for VMs are sized appropriately as are disk speeds, spindle numbers HBAs and multipathing however it is the disk that the Hypervisor runs on I mean.

At present, my company's standard is to use 2x 15k SAS disks in a RAID 1 config for the Hypervisor then attach LUNs from a SAN for VMs. If you say that the hypervisor runs entirely from memory once booted, then they might as well run from a USB/SD or internal SATA disks as you rightly said however if you have found this out somewhere along your travels (assuming you weren't born with this knowledge handed down from generation to generation) can you please provide some VMware literature to prove this as that would be what I require to change this expensive and unnecessary practice.

Thanks.

Poor attempt at humour - sorry I realise you are trying to help and I do appreciate it. ;)

Your 15k SAS drives would be put to better use in your SANs!

They are currently sitting there idle, not in use, other than when you boot them!

A waste of valuable resources.

Thanks for the help guys. It is a shame VMware don't have a document explaining that ESXi boots into memory and the disks are idle afterwards (the system does not use them to run like a full operating system).

I think I will have to gradually prove it (to my company) by speccing slower and slower disks and explaining how the USB/SD option works.

As it is an VCP exam question, it must be in the documents somewhere. As the VCP exam is based on experience and vSphere Documentation.

VMware vSphere 4.1 Documentation

VMware vSphere 4.1 Documentation Index

Hardware, Software, and Guest Operating System Compatibility Information

Hardware Compatibility Guide

Configuration Maximums for VMware vSphere 4.1

VMware vSphere Compatibility Matrixes

Guest Operating System Compatibility Guide

Main System Administrator Documentation Set

First published on 13 Jul 2010 for ESXi 4.1 Embedded Build 260247 and vCenter Server 4.1 Build 259021

Getting Started with ESXi Installable

ESXi Installable and vCenter Server Setup Guide

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