My immediate need is to provide storage for some RecordedTV currently on a failing PC.
To that end, I just pulled the trigger on an RN316.
My plan is to initially populate it with four 6-TB drives with the array formatted RAID-6 - which will be wretched excess for that purpose.
However....
Long-term, I would build the 316 up with a two more 6-TB drives, keep the the 5-TB-or-so of RecordedTV and then use the fully-populated 316 to replace my aging Ultra-6 and hold RecordedTV.
Once that is done and working for awhile, I would convert the Ultra-6 to OS-6 and use it as backup for the non-RecordedTV portion of the 316.
The Question: Are there practical problems around using 6-TB drives? .... Somewhere I got an impression that drive swaps/replacements took a loooooooooong time w/6-TB drives. ... Other considerations?
The Question: Are there practical problems around using 6-TB drives? .... Somewhere I got an impression that drive swaps/replacements took a loooooooooong time w/6-TB drives.
SmallNetbuilder reported about 3 hour resync time for 4x1TB RAID-5 in their (rather old) review. That scales linearly with volume size, so you should get about 18 hours with 4x6TB RAID-5 and about 27 hours with 6x6TB. They didn't measure RAID 6, but that will be significantly slower since the 2nd set of parity blocks is harder to compute.
You'd get faster resync times on an RN52x or RN62x of course. Though it might be better to use RAID-5 or even JBOD, and back up the recorded TV to the ultra (using the same disk configuration there).
I've used WD60EFRX in both an RN102 and an RN202 (jbod) and haven't had any problems. They are now in my RN526x (which runs 4x6TB XRAID). Performance is good, the temps tend to be in the 32-35C range with the RN526 fan set to "quiet". I might shift to "cool" in the summer, we'll see.
Some disks > 4 TB have dropped the side mounting holes - so you might need to remove the plastic inserts in the tray and use the old-school mounting screws. The WD60EFRX doesn't have that particular issue.
Note that some of these large disks are also using "alternative mount positions" on the bottom too. The trays shipped with RN52x NAS now have some new holes in the bottom to align with these new positions, but if your RN316 is older inventory it might not have those. You'll still be able to screw the disk into the tray, but you'll have to use fewer screws.
On my Ultra 6 running OS-4, I started out with 6 2-tb drives.
Eventually I upped it to having 6 3-tb drives and it was able to take advantage of all 3 terabytes on each drive.
But then I added a couple of 4-tb drives and hit the wall: it uses 3 tb of each, but to use the whole 4 tb, I would have to do a Factory Reset on the box and then re-load it from backup.
Bottom Line: What is the smallest size drives I can start out with on the 316 and still be able to upgrade to 6-tb drives later on without doing a Factory Reset and re-loading?
On my Ultra 6 running OS-4, I started out with 6 2-tb drives.
Eventually I upped it to having 6 3-tb drives and it was able to take advantage of all 3 terabytes on each drive.
But then I added a couple of 4-tb drives and hit the wall: it uses 3 tb of each, but to use the whole 4 tb, I would have to do a Factory Reset on the box and then re-load it from backup.
OS 4.2 has two XRAID expansion limits:
a volume can not expand over a 16 TiB ceiling
a volume cannot grow more than 8 TiB larger than it's initial size.
6x4TB exceeds both limits. You should have been able to upgrade to 3x4TB+3x3TB, unless you started with something smaller than 6x2TB when you did the factory install. Probably not worth troubleshooting now.
Bottom Line: What is the smallest size drives I can start out with on the 316 and still be able to upgrade to 6-tb drives later on without doing a Factory Reset and re-loading?
OS 6 doesn't have any known expansion limits. The smallest drive on the HCL is 80 GB, the biggest drive on the HCL is 10 TB. So if you stick with the HCL, you can expand from 1x80GB to 6x10TB. 6x12 TB probably also works, though I haven't seen any posts from people who are using 12 TB drives yet.
Note these limits would also disappear on your ultra if you switch to OS 6.
