2.5" HDD ?

mdgm wrote:
One of the things the NAS uses to control the fan speed is hard disk temps. Also the NAS uses SMART values to help detect some pending disk failures before they happen. So if it sees a disk temp of zero it probably thinks the SSD is failing/dead. The NAS is not programmed to handle differences between hard disks and SSDs.

I haven't tried it, so I guess I don't know how it would treat a 0 disk temp. I do know that one person posted success when installing SSDs into an ultra using a disk carrier that looks pretty similar to the one on this thread - viewtopic.php?f=24&t=45393#p279492 There were no followup posts, so of course we don't know how it worked out longer term. I think TRIM is the obvious issue, though if I understand it correctly it would hurt write performance more than read performance.

Anyway, we are off topic, since doubleplouc doesn't want to use SSD drives...

doubleplouc wrote:
I am not interested in SSD for a NAS, I would like a 2.5" HDD because it's easier to re-use in a mini-itx pc in case I would like to build a small home server one day (or USB-HDD or a smaller nas or whatever). It's more flexible to reuse than "big" 3.5. It is also supposed to be lower consumption and less noise (even if there are some good 3.5" for nas)....

Back on topic... I haven't tried this. But I do know from experience that many consumer drives that are not designed for RAID don't do so well in a NAS. If you want to try it, I suggest

(a) using whatever vibration/shock mount stuff that comes with your adapter. If there is nothing, you could pick up some silicone washers.
(b) I would also suggest using JBOD/independent RAID-0 with one volume per drive. I think a lot of the drive incompatibilities are related to maintaining the raid array when a read or write fails. So if your volumes don't span multiple disks, you might be on safer ground.
(c) as always, keep a backup on another device.