If you have total of 8TB and configure to use mirror (Raid 1) you will have only 4TB able to use .
Now, make sure that your hardware is compatible using HCL VMware Compatibility Guide - System Search
I have 4 x 4 TB hard drives. so 16 TB in two mirrors making it 8 TB total in two mirrors meaning 2 x 8 TB. I'm pretty new at doing this kind of thing. Would it better to have it a RAID 10? The problem i see with doing a RAID 10 though is that if I add more hard drives, which eventually I will be, how will I add this to the same data store?
If your server is having RAID-10 controller then I will recommended to go for RAID 10 only , it is combining advantage of RAID 0 and RAID-1 which always work faster, before do this activity, first test your hardware compatibility on VMware website whether it is supporting or not, if it is supporting then you will get 8 TB space for use.
Speed gain in RAID-10 – 4*read and 2*write speed gain
Fault tolerance- At least 1 drive failure.
What if I need to add more hard drives in the future and only want to add two at a time? Can I just add the new RAIDed hard drives to the datastore? also, why would ESXi only be seeing 3 TB out of the 4 TB?
Did you check HCL ? Maybe you need to install a specific driver.
After some careful inspection, the actual hard drive space is around 3762 GB so I guess VMware just rounded down. So I guess on that aspect everything is okay. My only thing is that I'm using this server as a cloud backup solution for my customers. So when I go to add new hard drives, I need to expand the datastore so I can expand the size of the hard drive. What would be the best way to go about that?
So, after a bunch of troubleshooting, I talked to my rep at Lenovo and they pointed me to a cd image for VMWare specifically for Lenovo products. After re-installing using that CD, everything is working properly. I can see the full capacity of the hard drives and i'm able to add both mirrored volumes to the datastore. Now on to the hard part of trying to transfer everything from the old server to the new one! Thanks everyone for your help!