> I wonder why Western Digital is almost absent, does anyone know why?
Most of the time the answer comes down to price/GByte. But it isn't QUITE as simple as that.
Backblaze tries to optimize for total cost most of the time. That isn't just the cost of the drive, a drive that is twice as large in storage still takes the same identical amount of rack space and often the same electricity as the drive that is half the storage. This means that we have a spreadsheet and calculate what the total cost over a 5 year expected lifespan will turn out to be. So for example, even if the drive that is twice as large costs MORE than twice as much it can still make sense to purchase it.
As to failure rates, Backblaze essentially doesn't care what the failure rate of a drive is, other than to factor that into the spreadsheet. If we think one particular drive fails 2% more of the time, we still buy it if it is 2% cheaper, make sense?
So that's the answer most of the time, although Backblaze is always making sure we have alternatives, so we're willing to purchase a small number of pretty much anybody's drives of pretty much any size in order to "qualify" them. It means we run one pod of 60 of them for a month or two, then we run a full vault of 1,200 of that drive type for a month or two, just in case a good deal floats by where we can buy a few thousand of that type of drive. We have some confidence they will work.