I need to expand the storage for my small business's dell R630 with a windows file server VM. We have a set of 5 matching brand new hard drives (3.5in 5400rpm wd red 6TB) that we would like to use. I know the standard answer is to buy a power vault or other direct attached storage device, but as far as I can tell these all require buying SAS drives with the purchase of the device, and will cost us a relative arm & leg (over $5000) to get to 30TB raw space. I am considering buying an inexpensive synology NAS ($700) and running a gigabit ethernet cable straight from it to the R630. I'll create a virtual disk on the NAS and mount it as the non-system drive in the VM.
For reference, the business currently uses lower capacity 5400rpm drives that are plugged straight into the server, but a larger capacity raid is needed with more space and more total drives for RAID 6, hence we can no longer fit the drives in the R630s built in drive bays. The current performance is fine, but I want to avoid a decrease in performance.
My question is this: Will using a virtual disk on a NAS be noticeably slower than having 5400 rpm drives in the server?
I am guessing no, because all users will be accessing the file server over gigabit Ethernet anyway, so the network bottleneck is already in place.
As pointed out in the comments, noticeably slower is subjective. I would consider plus/minus 10% to be acceptable, but more than 10% slower would be a problem.