I have a doubt ... but can you use an external hard drive?
External drives are slow to plot on, but you can mine on them just fine even the SMR-based drives like the Seagate Archive line (which are pretty much perfect for BURST usage).
You advice seagate as external hard disk?
Their external 8GB (which is USUALLY an Archive drive inside) is commonly the lowest cost/GB on the market, and tends to cost less than buying the bare drive.
Poloniex has had "issues" with slow deposits and slow withdrawals for MANY MONTHS now - among other issues.
I strongly recommend avoiding them.