Utilizing Local Storage on ESX for High Availability

With the cost of FiberChannel, NAS and other external storage being as costly as they are, we are looking at other options to get some storage for our ESX hosts.  Right now we are utilizing ESX with Vmotion.  We wanted to find a way to utilize the large amount of local disk that we can not use on our production VMs as they do not allow for vMotion and being used as a cluster resource.  In the past to add space we have had a lot of success using OpenFiler on some older hardware and connecting it  to the local hosts via iSCSI.  This is great, but we still are not using the local storage.  This was great because old machines are plentiful and Harddrive space is cheap, however we are still wasting the local disk. 

During a standard bantering session between myself and some other guys at the office, we came up with an idea.  We decided to create a VM on each virtual host.  We then gave those VMs a large chunck of the local disk.  Once that was done, we were then able to connect all of the other machines to each openfiler VMs “local disk”  Poof, quick and simple solution to use that storage and be able to vmotion your machines and SV motion the disks from those machines between all your hosts.  So far this has been done and seems to be working excellent. 

Plan two of this process is going to be setting up rsync between pairs of virtual servers, basically replicating the local disk between two different ESX host machines.  This helps to add another layer of redundancy against single host failure.  Now, if a physical machine fails, the machines that had HDs on that local host, can be restored via reregistering its vmdks on the other openfiler rsync partner.  This has not been tested but is phase two in our implementation of this.  This is obviously not seemless but still offeres a little bit of protection.