3 or 4TB for raid 5 or Synology hybrid raid?

[cyber69]

I'm mulling over purchasing 4 new drives to put into a 4 bay Synology unit, either a DS415 play or DS415+ and can't decide between 3TB or 4TB size.

I've read that if you go higher than 3TB you increase the risk of getting errors in the raid when doing a rebuild which is why most enterprise drives are less than 3TB in size.

I've got a Synology DS412+ unit with 4 Western Digital reds and that has served me well for the past 3 years but rather than buy the DX expansion I think I will get another unit and run them together.

 

[MajorMaccas]

Raid 5 is dead due to the size of HDDs. It comes down to the MTBF, the number of sectors on a huge 3TB drive, and how parity works during a rebuild.

Raid 6 is far more resilient, but with your setup of 4 drives, if you're going to use 2 for parity you may as well just mirror for far more performance, far safer data, and quicker and safer rebuilds.