Users want cheap disk. They don’t know it, but they also want fast disk. IT in turn wants reliable disk.
IT has several options to provide disk to services: local disk, external SCSI/etc-attached disk drawers, SAN-attached disk, NAS devices (e.g. NetApp CIFS/NFS disk), iSCSI, all of the above served via NFS/CIFS/AFS/GPFS/GFS/other protocols, …
So I started by looking at commodity hard drives, via Tom’s Hardware. You can even sort by cost per gigabyte. The hard drives here are ultra-junky.
My thinking right now is that cheap local server disk is a reasonable trade-off: useful, RAID-enabled disk and CPU to boot. Dell/etc let you put six 750 gb SCSI II 7200 rpm drives in. I mean your drives will be slow, but with RAID-1 you’d still get over two terabytes of storage–and a dual-CPU machine that serve out the disk and do something else too.