The friendly folks at Backblaze are back with the latest installment of their drive reliability series - now with 4TB drive data. Brian Beach's post is here.

Key points:

4TB HGST and Seagate drives are much more reliable than 3TB drives, with an annual failure rate (AFR) of only 2.6 percent vs 9.3 percent for 3TB drives.

They don't have good numbers for WD 4TB drives because they cost more, so they haven't bought many.

HGST drives are more reliable than Seagate drives, but not enough for Backblaze to favor them over Seagate. But you might.

6TB drives are too new to have a track record, but they're buying more.

Here's a chart comparing failure rates in 2013 (gray bars) to 2014.

Courtesy Backblaze

The Storage Bits take

There were some teething pains with the 3TB drives, but it looks like the kinks were worked out with the 4TB drives. That's a good thing because my 3TB Seagate is filling up.

For those of buying one or two drives, this data is more comforting than conclusive. You never know if the couple of drives you buy come from a rare bad batch or got dropped by the shipping clerk.

But you improve your odds by following it. And it does confirm one piece of industry scuttlebutt: HGST makes high-quality drives.

Comments welcome, as always. There were some objections to Backblaze's numbers last year and here's my response.