Stefan Monnier writes:
Peter Ehlert [2021-08-03 08:27:26] wrote:> On August 3, 2021 8:17:58 AM Stefan Monnier <monn...@iro.umontreal.ca> wrote:>>> Second, the price of spinning disks is such that it makes no >>> sense to buy anything smaller than 4TB, which will fit all this, >>> and 6-8 TB are often a reasonable idea even for single users. >> You seem to assume a 3½" form factor which either requires a "large" >> desktop or an external enclosure. > Not really. My HP z620 work station ain't huge.
[...]
>> Personally I consider this form factor dead every since I bought my >> first 2TB 2½" disk.> If you use Lots of drives (4tb), and are on a limited budget, like me... > The 3.5 form factor is more cost effective.That's why I wrote "personally". AFAIK the proportion of computer users which "use lots of drives" is quite small. Maybe it's higher among
Four internal drives here (2x3.5" HDD, 2x2.5" SSD), not sure if that counts as a lot.
Debian users, admittedly, but still your original statement above lacks a qualification like "AFAIC" or "IMO" ;-) OK, to add actual info to this message, here's a quick look at today's lowest prices in my "usual" store: 2TB $ 64 3½ HDD 32 $/TB 3TB $ 65 3½" HDD 22 $/TB 4TB $104 3½" HDD 26 $/TB 6TB $139 3½" HDD (external) 23 $/TB 8TB $199 3½" HDD 25 $/TB 10TB $323 3½" HDD (external) 32 $/TB 12TB $339 3½" HDD (external) 28 $/TB I'm surprised at how stable the price per TB is over the 2-12 range. It used to be the case that HDD price's curve was not nearly as linear (which reflected the fact that production costs aren't (weren't?) proportional to the drive's capacity). I suspect that the profit margin varies widely over this spectrum.
Thank you for putting the numbers together. It is always nice to see some current statistics about it. From memory, 6-8T used to be the sweet spot.
2TB $ 60 2½" HDD (external) 30 $/TB 3TB $125 2½" HDD (external) 42 $/TB (only "recertified" available) 4TB $114 2½" HDD (external) 29 $/TB 5TB $139 2½" HDD (external) 28 $/TB It's also interesting to see that the price per TB is about the same for 2½" HDD as for 3½" HDD, whereas it used to be significantly higher. [ And also that in the 2½" space, your best bet in $/GB is to buy a drive+enclosure, which implies you don't really know what you're getting other than the capacity of the drive. :-( ] That makes 3½" form factor even more dead than I thought (two 4TB 2½" drives should offer better performance than one 8GB 3½" drive and use less space, not sure about power consumption).
[...]I still use and like the 3.5" drives mostly due to the following considerations:
* It is easier to get 3.5" at 7200 rpm than 2.5". Faster rotation means faster access and this is usually where HDDs are very slow hence I do not want them to be even slower. * 3.5" drives are available with CMR even at high capacities like 6T oder 8T. With 2.5" a limited and expensive selection of server drives offer 2T or 4T with CMR, whereas AFAIK all consumer-grade 2.5" hard drives above 1T are SMR drives. I am not sure if there are any 2.5" CMR hard drives (server or not) above 4T?This means in terms of performance, it is quite possible for a single 3.5" drive to outperform two 2.5" ones (unless you are only doing sequential reads from two drives in parallel).
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