Question: I have 6 1tb drives in a RAID5. 1 drive went down. On the RAID was 2 virtual machines that I really need back up and running. The spare drive I have to put in the server is a 1.5tb drive, which exceeds the physical per drive limit of the 2020SA. The drive is found in the disk utility, but it is not found in the array management section. I cannot add the drive to the array to have it rebuild. 

I have a replacement drive along with some spares on their way from Newegg, but I am still looking at a few days of downtime. Is it possible to use the 5 working drives to get the VMs copied off and on to another server or do I just have to wait for the drives to get here?

Answer: 
The whole point of a Redundant Array of Inexpensive Disks is that there is redundancy built in, at some level. A raid 5 array should have survived a single disk loss. That card does support ot swap so the failure should have been invisible as far as IO is concerned. The max Array size (I think ) is only 2 TB so I wonder if your issue is compounded by creating an array too large?
> 
> Is it possible to use the 5 working drives to get the VMs copied off
>  and on to another server or do I just have to wait for the drives to
>  get here?
> 
> 
> 

Did the server actually go down? if so then the array's not doing what it should, i.e. allow you to survive a single disk failure, if it stayed up then you may as well copy the VMs off now, in fact I'd recommend it.

By the way, RAID 5 arrays of large disks, especially SATA ones is a terrible idea, search around on this site to spot the tails of woe from others in this situation.