Investigating beyond RAID for disk cluster in a server, is Dynamic Disk Pool comparable?

For a single system, I would really suggest to stick with well know and performing RAID arrays. Object stores have significant performance penalty compared to classical block/file access and, if you don't scale out, you lose many of their benefits.

That said, excluding classical RAID you have the following possibilities:

• unraid, which uses a file-level replication approach rather than a block-level one

• glusterfs, configuring a different brick for each disk and applying a replica 2 policy

• zfs which, albeit block-based, is not 100% identical to classical software or hardware RAID

Also note that object storage does not guarantee lower rebuild time; quite the contrary, it tackles long rebuilds by guarantee stronger replication policies (ie: replica 3 over different racks).

"that will ensure data safety but without the drawback of huge rebuild time when replacing a disk"

You have a delusion in that you think software can change reality - i.e. physics. The hugh rebuild times essentially run down to having to write a compelete Disc and if you write 2tb of info on a disc it takes a long time BECAUSE THAT IS HOW DISCS BEHAVE. Particualarly if you HAVE to read multiple discs to get the missing data in the first pleace (Raid 5,6 analog). There are details in how "stupid" software can be (i.e. add time on top of the physical minimum), but the minimum already is hours if you talk of slow large SATA discs.

All other technology you mention has to adhere to the same problematic large time you want to avoid because - physics.

And it does not help that your cluster network - if you do replication of the the network - is using 10g or lower (which is the most likely case) instead of going 40g or 100g.