× NETGEAR will be terminating ReadyCLOUD service by July 1st, 2023. For more details click here.
Orbi WiFi 7 RBE973
Reply

rn214 increase RAID 5 capacity by installing larger disks.

BionicManster
Aspirant

rn214 increase RAID 5 capacity by installing larger disks.

I have a RN214 that I got years ago, and I love it. It is loaded with 4, 8TB disks in a RAID 5 configuration which gives me 21.8 TB usable space. Unfortunately it is filling up.

I know that if I use differently sized disks, the RAID will be based on the smallest of them. But if I replace the 8TB disks with 14TB disks one at a time, allowing the unit to format the new disk and update the RAID, once I have replaced the 4th one, can I increase the RAID size without doing a backup, format, and reload?

OS version 6.10.1

 

Thanks!

Message 1 of 6

Accepted Solutions
BionicManster
Aspirant

Re: rn214 increase RAID 5 capacity by installing larger disks.

Once again, I appreciate the insight. I'm afraid I always get Raid 0 and 1 confused. I always think Raid 1 is JBOD, just a bunch of disks concatenated together into a single virtual disk.

If I had the ability to back up 19 TBs I would. I'm just going to have to save the most important stuff and hope for the best.

As to why trust RAID 5, well, that's the point isn't it? I may well be able to afford $1800, but my money is still limited. RAID 5 or RAID 1, either can support a single disk failure. There's double the number of opportunities with RAID 5, but there's also 3/4th of the raw storage of the disks instead of 1/2. IronWolf drives have an MTBF of 1 million hours (114 years) so I don't think it's too much of a risk.

Anyway, I also have a RN104, which is currently stocked with four 4TB drives, or 10.6 TB space which is about 90% full. Because of what you told me, I think I'll copy as much of it as I can to the RN214, back up as much as I can of the rest, and then stick the new disks in it. Same space increase, less risk.

I will take it slow, put one disk in, run the re-sync, and let it stabilize for a week before putting in the next one. At least I can eliminate the intermediate RAID 1 step you mentioned, saving that until I am ready to make the new space into a RAID 5.

Thanks again for your help.

View solution in original post

Message 6 of 6

All Replies
Sandshark
Sensei

Re: rn214 increase RAID 5 capacity by installing larger disks.

ReadyNAS XRAID on OS6 units is even more versatile than that.  If you replace just two 8TB's with 14TB's (one at a time), your volume will grow by 6TB.  The additional 6TB of each of the two 14TB will be in RAID1 and concatenated with the existing volume.  If you replace another with a 14TB, which could be months from now, it will convert the three extra 6TB partitions to RAID5 and it'll grow another 6TB.  And a fourth will grow it yet another 6TB.

 

Each added drive needs to re-sync, so you have to wait before adding the next one.  And from drive 2 on, it'll require two syncs -- one for the layer made of 8TB partitions and one for the additional 6TB.

 

I recommend you only grow the volume as you need to.  That spreads the drive acquisitions over a period of time, making concurrent failure (including infant mortality) less likely.  The price of 14TB drives will likely fall, too.

Message 2 of 6
BionicManster
Aspirant

Re: rn214 increase RAID 5 capacity by installing larger disks.

I really appreciate the thoughtful and informative reply.

But I don't want to depend on RAID 1. The reason I got the NAS was to have RAID 5 redundancy, to make sure I don't lose files.

I was prepared to buy a whole new RN424 and populate it with 12TB IronWolf drives, for about $1800, when I thought about upgrading my current unit instead of adding a new one.

if I follow you advice, adding one drive at a time and re-sync after each, will there be a way after I add the 4th drive to just increase the RAID 5 size?

Thanks again!

Model: RN214|4 BAY Desktop ReadyNAS Storage
Message 3 of 6
BionicManster
Aspirant

Re: rn214 increase RAID 5 capacity by installing larger disks.

P.S. I'd accept adding them as RAID 0, if it doesn't disturb my current RAID 5 set up.

 

Message 4 of 6
StephenB
Guru

Re: rn214 increase RAID 5 capacity by installing larger disks.


@BionicManster wrote:


But I don't want to depend on RAID 1. The reason I got the NAS was to have RAID 5 redundancy, to make sure I don't lose files.

Why are you thinking that RAID-5 is safer than RAID-1?  Both provide the same protection - guarding against the loss of one disk.  RAID-5 is actually more fragile than RAID-1, and it is harder to recover data from a compromised RAID-5 array than it is to recover data form a compromised RAID-1 array.

 

In any event, RAID in any form isn't enough to keep your data safe - it is a big mistake to think that it is.  The only way to keep your data safe is to have at least one copy on other device.  Ideally you'd have at least 2 other copies (one off-site for disaster recovery).

 


@BionicManster wrote:

if I follow you advice, adding one drive at a time and re-sync after each, will there be a way after I add the 4th drive to just increase the RAID 5 size?


Here's what happens with XRAID:

 

  1. When you upgrade the first first 8 TB drive with a 14 TB drive, the existing RAID-5 array is resynced, and the extra 6 TB of space on that disk isn't used.
  2. When you upgrade the second disk, the existing RAID-5 array is again resynced. The system then creates a second RAID-array (also called a RAID group) that uses the extra size TB of space.  So you end up with two RAID groups - 4x8TB RAID-5 + 2x6TB RAID-1.  Both of these are concatenated together into a single volume (which would be 30 TB altogether).
  3. When you upgrade the third disk, the first RAID-5 group is resynced, and the second RAID-1 group is converted to RAID-5.  You end up with 4x8TB RAID-5 + 3x6TB RAID-5, or 36 TB all together.
  4. When you upgrade the fourth disk, the first RAID group is again resynced, and the second RAID-5 group is horizontally expanded.  You end up with 4x8TB RAID-5 + 4x6 TB RAID-5 (42 TB in the final volume). This gives you the same space as a 4x14 TB RAID-5 array, but it is organized a bit differently under the covers.

This process does require a lot of disk I/O, and if you are upgrading all the drives in one go, then it would be faster to back up the data, do and rebuild the system from scratch with all the new disks in place.  Then restore the data from backup.

 

And we do recommend a backup.  If any of the existing disks fail when you are upgrading one, then the entire array fails, and you lose all your data.  One of the downsides of RAID-5 btw.

 

Message 5 of 6
BionicManster
Aspirant

Re: rn214 increase RAID 5 capacity by installing larger disks.

Once again, I appreciate the insight. I'm afraid I always get Raid 0 and 1 confused. I always think Raid 1 is JBOD, just a bunch of disks concatenated together into a single virtual disk.

If I had the ability to back up 19 TBs I would. I'm just going to have to save the most important stuff and hope for the best.

As to why trust RAID 5, well, that's the point isn't it? I may well be able to afford $1800, but my money is still limited. RAID 5 or RAID 1, either can support a single disk failure. There's double the number of opportunities with RAID 5, but there's also 3/4th of the raw storage of the disks instead of 1/2. IronWolf drives have an MTBF of 1 million hours (114 years) so I don't think it's too much of a risk.

Anyway, I also have a RN104, which is currently stocked with four 4TB drives, or 10.6 TB space which is about 90% full. Because of what you told me, I think I'll copy as much of it as I can to the RN214, back up as much as I can of the rest, and then stick the new disks in it. Same space increase, less risk.

I will take it slow, put one disk in, run the re-sync, and let it stabilize for a week before putting in the next one. At least I can eliminate the intermediate RAID 1 step you mentioned, saving that until I am ready to make the new space into a RAID 5.

Thanks again for your help.

Message 6 of 6
Top Contributors
Discussion stats
  • 5 replies
  • 1860 views
  • 2 kudos
  • 3 in conversation
Announcements