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I'd like to be sure I understand properly and will take the correct steps.
ReadyNas Pro 4 XRAID2
Raidiator -x86 4.2.31
Raid Level X-RAID2 4 disks
(my accessing units are mostly windows 7 & 10)
I thought I set it up with redudundancy because even though I had 4x1T disks, I only ever had about 2T. So I thought that my disks were duplicated.
But now I have the error below. Does it just mean I have to replace disk 1 and then i will get my redundancy back?
Also, I am hitting my storage limit. Can I replace with (supported) 4x3T drives (one by one starting with goner)? I THINK that will keep me under the 8T max expansion limit.
I do have data backed up on Carbonite and I've tested the recovery (different saga).
But that process is slow so I'd rather do the hot swap route if possible.
TIA!
T
Configuration:RAID Level X-RAID2, 4 disks
Status:Not redundant. A disk failure will render this volume dead.
RAID Disks:
Ch 1 : WDC WD1002FBYS-02A6B0 [931 GB] had not-green dot next to it
Thank you! I feel reassured about the replacement.
I had read ages ago about teh parity but forgotten - or as i say I must have slept since then. Thank you for explaining it in more detail. Pretty neat.
One follow up regarding replacement drive size.
I found in another post - by you I believe - the concept of
""sum the disks and subtract the largest". " to find storage space in Raid 5.
Using this format, - again my orig confi is 4x1TB
Can I use 4x4TB replacements and still be under the 8 TB expansion limit.?
The growth would be 9 TB (since your starting point was a 3 TB volume, and 4x4TB would give you a 12 TB volume). 9 TB is ~8.2 TiB, which unfortunately that is just over the limit.
I thought I set it up with redudundancy because even though I had 4x1T disks, I only ever had about 2T. So I thought that my disks were duplicated.
But now I have the error below. Does it just mean I have to replace disk 1 and then i will get my redundancy back?
Configuration:RAID Level X-RAID2, 4 disks
Status:Not redundant. A disk failure will render this volume dead.
RAID Disks:
Ch 1 : WDC WD1002FBYS-02A6B0 [931 GB] had not-green dot next to it
Replacing disk 1 will restore your redundancy.
4x1TB X-RAID2 uses standard RAID-5. So the capacity would be 3 TB. However, the Web UI actually reports the size in TiB (1024*1024*1024*1024 byte = 1 TiB) - so it should report ~2.7 TiB.
FWIW, the disks aren't duplicated - the redundancy is provided in a different way. The disks are organized into data blocks and parity blocks - for example you'd have data block A on disk 1, data block B on disk 2, data block C on disk 3, and parity block P on disk 4.
The partity block P is computed from A, B, C.
P=A+B+C
The actual partity block construction doesn't use addition (it uses XOR), but you can think of it as addition. Every time you update one of the data blocks, the NAS recomputes the associated parity block.
Then if a disk fails or is replaced, you can reconstruct the missing block using one of the equations below:
A=B+C-P
B=A+C-P
C=A+B-P
P=A+B+C
In this example the first equation would apply. Note that the parity block isn't always on disk 4, the pattern is rotated so that some partity blocks are on each disk.
Also, I am hitting my storage limit. Can I replace with (supported) 4x3T drives (one by one starting with goner)? I THINK that will keep me under the 8T max expansion limit.
You should be fine. 4x3TB gives you a 9 TB volume (~8.2 TiB). So even if you started with a single 1 TB drive you'd still be under the 8 TiB expansion limit (expanding about ~6.4 TiB ).
Thank you! I feel reassured about the replacement.
I had read ages ago about teh parity but forgotten - or as i say I must have slept since then. Thank you for explaining it in more detail. Pretty neat.
One follow up regarding replacement drive size.
I found in another post - by you I believe - the concept of
""sum the disks and subtract the largest". " to find storage space in Raid 5.
Using this format, - again my orig confi is 4x1TB - 3TB
Can I use 4x4TB replacements and still be under the 8 TB expansion limit.?
Thank you! I feel reassured about the replacement.
I had read ages ago about teh parity but forgotten - or as i say I must have slept since then. Thank you for explaining it in more detail. Pretty neat.
One follow up regarding replacement drive size.
I found in another post - by you I believe - the concept of
""sum the disks and subtract the largest". " to find storage space in Raid 5.
Using this format, - again my orig confi is 4x1TB
Can I use 4x4TB replacements and still be under the 8 TB expansion limit.?
The growth would be 9 TB (since your starting point was a 3 TB volume, and 4x4TB would give you a 12 TB volume). 9 TB is ~8.2 TiB, which unfortunately that is just over the limit.
One option open to you @TMcL is to convert your Pro 4 operating system to the current one of OS 6, this has no expansion limits
The process involves reformatting the disks, so you do need a full backup if you want to do that. Going to 4x4TB requires destroying the data 4.2.31 anyway, so if you want that size you should certainly consider converting. Many folks have here have done it. Some of the other advantages are that you'd have SMB 3 (current version of SMB used by Windows 10), have a current of version of linux, and be able to use ReadyCloud and Plex.
The downside is that Netgear won't offer paid support if you convert.
My own Pro-6 is still running 4.2.31, and is at it's expansion ceiling. When/if I need more space I plan to convert it.
Thank you @bedlam1 and @StephenB. I’m keeping it simple this time around. When I have time to revamp my network without work and family projects I’ll expand. For now I’m pulling the dead drive and inserting the new one. I’m sure you’ll be the first to hear if something goes awry. Lol. Thanks again!
