Raid10 - benefits of replacing SATA drives with SAS
Posted on 2016-10-26
Dell poweredge R420 with Perc 710 controller. Currently RAID10 with 4 2TB WD NAS SATA drives. No problems other than we'd like to see some more RAID throughput. This server is used as an iSCSI SAN for a VM environment - OS is Windows 2012 R2 - running Starwind SAN. I have seen where IOPS are nominally twice as high with SAS compared to SATA. When I built the server a few years ago SAS drives were still pricey - but now a 2TB drive is $100+. So - will I see a decent speed increase in the iSCSI transfers? If so, can I just replace these drives one at a time, letting the array rebuild between replacements? Or will the PERC complain if I mix SAS and SATA (temporarily). Or is there any way to do an image copy of each array member SATA drive to a new SAS drive and then fire it up with all SAS? Intuitively this seems like it will work but likely there are geometry differences and I know that can screw up RAID.
I don't have any place to backup the entire SAN partition anywhere - at 3.8 TB it's too big. I would have to backup individual VMs and reload each one after restoring the OS partition. Obviously replacing one drive at a time would be MUCH simpler.