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Forum Discussion
Max_NAS
Aug 23, 2018Tutor
ReadyNAS 316 additional drives
I have two 3.0TB WD Red drives (WD30EFRX, September 2014) in my 6 bay RE316.
It's time to expand my data capacity, and I was hoping someone could advise on my best options.
Would I need to buy an...
- Aug 23, 2018
Max_NAS wrote:
I have two 3.0TB WD Red drives (WD30EFRX, September 2014) in my 6 bay RE316.
It's time to expand my data capacity, and I was hoping someone could advise on my best options.
Would I need to buy another pair of the same drives to double capacity? Or can I install a single higher capacity drive?
The capacity rule for XRAID single redundancy is "sum the drives and subtract the largest". So in your case adding one additional 3 TB drive will double your capacity.
You could add a larger drive (say a 6 TB WD60EFRX), but you'd only be using 3 TB of it's capacity until you added a second one of that size. Some do plan ahead and do that - over the long haul, larger drives are often more cost effective. But you still have plenty of empty bays, and if your storage needs are growing slowly it might not be a good strategy for you.
You can't add a smaller drive though.
Max_NAS
Apr 07, 2025Tutor
Hi all,
I'm starting to get capacity notifications again, so it's time to add a new hard drive(s).
As my ReadyNAS 316 is 10 years old, and two of the three WD Red 3Tb drives also quite old, I decided to run a disk test - but have no idea how long it's going to run for or what kind or results to expect (see attached).
Regardless of the results, would the community recommend adding a new WD Red to my current system? It seems WD Red 3Tb is no longer available, but a WD Red Plus 4Tb should give me 3Tb. (3+3+3+4-4 = 9Tb)
Or should I replace all drives to be safe?
Thanks,
- SandsharkApr 07, 2025Sensei - Experienced User
Not an easy question to answer, since it depends a lot on your specific use. It especially matters how much a volume failure would cost you (in time, lost data is you have no backup, etc.) vs. real cost for more new drives. Are you currently seeing any ATA errors, re-allocated sectors, or pending sectors? If you are, then replacement begins to look even better.
Keep in mind that at some time you're going to need to replace those three older drives. That means three re-sync operations, which are hard on drives. Failure of a second drive during re-sync and subsequent loss of the volume is more likely to occur with older drives.
Keep in mind you don't have to replace them all to get full use with bigger ones -- just two. Swapping two for 6TB ones also gives you an extra 3TB and swapping two for 8TBs gives you an additional 5TB. Then you can still replace the last one later for an additional 3 or 5TB. For me, 8TB drives is currently my minimum unless I'm recycling old ones. Anything smaller costs more per TB.
BTW, if you put them in alternating bays (1,3,5 or 2,4,6) they'll run a little cooler.
- Max_NASApr 08, 2025Tutor
Thank you Sandshark and StephenB for your responses - it's reassuring to know this community is really helpful!
Quick summary of my RE316 use;
1. Mostly storage of old project files (CAD, 3d models, renderings, videos), each project in 10-30Gb zip files.
2. Archives of old cad software, photos, music, etc.
3. Also backup of C: drive.
4. Power on at 9am, off at 11pm every week day.
5. Incremental backups of current project files from PC to NAS using Acronis, every 3 hours.
6. Daily backups of C: drive
7. Occasional retrieval of old project files (ie. copying 30Gb zip files back to PC)
8. Never snapshots
9. Acronis creates one full backup version after every 10 incremental backups.The disk test I ran last night returned "Disk test failed on disk in channel 4, model WDC_WD30EFRX-68EUZNO, serial, etc.". This is the first time I've seen an error in the 10 years I've had this NAS, is it something to worry about?
Thanks for the info about staggering them into 2,4,6 - I didn't know that was possible.Question now is - do I need to urgently replace the channel 4 disk, or should I add more disks or remove contents to get back down to say 50% total capacity and survive another few years?
- SandsharkApr 08, 2025Sensei - Experienced User
Reducing the amount of data isn't going to help. The data ,is striped across all drives, it doesn't start filling one and go to the next, etc. If you have one failing drive and the others are the same or similar age, more failures are likely in your near future. Unfortunately, that could be when re-syncing a drive, which usually kills the volume.
Since you have a mix of archival files and backups, I hope you have at least a partial backup plan for anything that you can't tolerate losing. Make sure that backup is up to date before you start with any drive swaps. After backup, you should replace that drive before you consider adding another. And it sounds like replacement of all three is a good idea.
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