Make your own SAN using iSCSI for VMware ESXi? Think twice!

 ESXi, VMware, vSphere  2 Responses »
Sep 282010
 

Last night I was working on my vSphere test cluster, and an old memory popped up into mind. I just want to share on my blog since this extremely important peice of information could affect you or one of your own deployments.

There are numerous guides on the internet out there telling you how to set up your own SAN or NAS using iSCSI for your own ESXi boxes. One thing these guides don’t factor in is environments that have multiple ESXi hosts.

VMware ESXi (and ESX) when using iSCSi and a shared VMFS volume, require an iSCSI target (iSCSI server) that supports SCSI reservations. Most opensource iSCSI targets like IETD (iSCSI Enterprise Target) DO NOT SUPPORT this standard as of the time of this article being written.

With this being said, operating an iSCSI VMFS volume shared to multiple hosts could ultimately end up in corruption and data loss.

One opensource iSCSI target that I know of that DOES support SCSI reservations is Lio-Target (available here). I personally haven’t experimented with it, but it does support it. One of these days I’m going to do some of my own testing with it.

Keep in mind that instead of using iSCSI you could alternatively use NFS. I use NFS at my company and it works great as a ESXi data store for 3 ESXi boxes. For those of you curious, NFS data stores DO support High Availability (FT), and Vmotion!

UPDATE: Tried out FreeNAS running on a SuperMicro Server with a HP Smart Array 6400 Array controller with an MSA20 storage unit. FreeNAS started spewing a very large amount of errors when accessing VMFS over iSCSI. I think this could be due to some of the disks I have in the array that aren’t being flagged as bad, but are in fact bad.

Installing ESXi on to a USB Key/Flash drive

 ESXi, VMware, vSphere  No Responses »
Apr 112010
 

First off, I’d like to say this is my first post on my new personal blog. Please be sure to check out my other blog I maintain for my company at https://www.digitallyaccurate.com/blog!

I thought I’d make the first post in relation to one of my most favorite things to play with; ESXi.

All over the internet there are many tutorials on putting ESXi on to a USB key using the installer image, and dd command on a working linux install. Here at my office, we have a HP Proliant ML350 G5 running ESXi. We didn’t use the method on these tutorials as there is an easier method.

First download the applicable VMware ESXi 4.X installer image (I’ve included links to the standard installer along with the special HP installer to take advantage of the HP monitoring hardware):

ESXi 4.X Standard Install

http://www.vmware.com/go/get-free-esxi

HP ESXi 4.X Installer (Includes HP CIM Provider)

https://h20392.www2.hp.com/portal/swdepot/displayProductInfo.do?productNumber=HPVM06

Please note: I’ve seen a few tech documents stating different sizes required for the USB key. However in all my cases a simple 1GB usb key has worked great!

After downloading the ISO installer for VMware, burn it to a disk.

Insert the empty USB key into the server. If you using a HP server with the hidden USB ports on the main board, insert the usb key now aswell.

Boot off the CD and proceed with the typical VMware ESXi installation, however when it asks you what disk you would like to install ESXi to, choose the USB flash drive.

Follow through with the installation, and you now have a USB key with ESXi installed on it.

In my oppinion, I find this way easier and less time consuming then manually dd’ing the image from the compressed archives onto the USB key using a Linux system. It works, but like I said this method is easier, and takes up less time. (And I always feel safer using the manufacturers installer rather than manually moving/writing hidden images inside of installers).

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