> What is the best way to setup shared storage?
> 1. Add more hard drives to server?
> 2. Just buy a second server?
You have two options:
A.
Setup VSAN. you will need to setup another nested esxi server. follow this link
http://www.virtuallyghetto.com/2013/09/how-to-quickly-setup-and-test-vmware.html
B.
for you existing 2 esxi servers, you can add shared storage which would come from your physical server
from your physical server,
power off nested esxi servers.
i. edit virtual machine settings of one nested esxi server VM from UI and add a New device "SCSI controller" from select menu
ii. Expand this newly added SCSI controller and choose the SCSI Bus Sharing option to "Virtual". Meaning Virtual disks can be shared between virtual machines on the same server
iii. After this add a harddisk from the New device-> select drop down menu. Expand the newly Newly added "Hard disk" and under "Virtual device Node" selection box choose the "New SCSI controller" added.
from the other nested esxi server, repeat the above steps (i & ii) and then select "Existing Hard Disk" option from the "New device -> select" drop down menu and from browse menu choose the virtual disk added in step (iii)
Then power-on both nested esxi server VMs. you will be able to see the added harddisk shared between two nested esxi servers
Thanks,