ReadyNAS Ultra 4 - Total capacity does not add up

[eyl4j]

Hello,

I have a Netgear ReadyNAS Ultra 4.  Initially, I had two 2 TB HDs that resulted to a capacity of around 1.8 TiB.  I then expanded it with two 4 TB HDs.  Based on http://rdconfigurator.netgear.com/raid/index.html, my expectation was that the total resulting capacity after expansion would be 7.25 TiB (~8 TB minus overheads).

However, the total capacity ends up being 5548 GiB.

Following is some additional info copied from the web interface:

RAID Configuration

Configuration:	RAID Level X-RAID2, 4 disks
Status:	Redundant

RAID Disks:

	Ch 1 : Seagate ST32000542AS [1863 GB]	1858 GB allocated
	Ch 2 : Seagate ST32000542AS [1863 GB]	1858 GB allocated
	Ch 3 : Seagate ST4000VN000-2AH166 [1678 GB]	1858 GB allocated
	Ch 4 : Seagate ST4000VN000-2AH166 [1678 GB]	1858 GB allocated

In particular, I find the information for Ch3 and Ch4 very puzzling... especially since, the RAIDar on my PC shows these channels as being 3726 GB, not 1678 GB with 1858 allocated (!?) as per the web interface.

I would appreciate any potential insight and/or suggestion that would explain or fix this.  Thank you in advance.

Eric

[StephenB · Accepted solution]

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@eyl4j wrote:
In particular, I find the information for Ch3 and Ch4 very puzzling... especially since, the RAIDar on my PC shows these channels as being 3726 GB, not 1678 GB with 1858 allocated (!?) as per the web interface.

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I find it puzzling also; it isn't adding up as it should.  And I agree that the volume size with that disk configuration should be ~7.25 TiB.  What firmware are you running?

Perhaps reboot the NAS once or twice, and see if it starts expanding.

If that fails, you might try removing one of the 4 TB disks and reinserting it with the NAS running.  If seems to get you the proper disk size, then (after resync) do the same with the other 4 TB disk.

I suggest making a full backup before you remove/reinsert disks, as something is definitely wrong.

[bedlam1]

Maybe a look at THIS may help

[StephenB · Accepted solution]

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@eyl4j wrote:
In particular, I find the information for Ch3 and Ch4 very puzzling... especially since, the RAIDar on my PC shows these channels as being 3726 GB, not 1678 GB with 1858 allocated (!?) as per the web interface.

---

I find it puzzling also; it isn't adding up as it should.  And I agree that the volume size with that disk configuration should be ~7.25 TiB.  What firmware are you running?

Perhaps reboot the NAS once or twice, and see if it starts expanding.

If that fails, you might try removing one of the 4 TB disks and reinserting it with the NAS running.  If seems to get you the proper disk size, then (after resync) do the same with the other 4 TB disk.

I suggest making a full backup before you remove/reinsert disks, as something is definitely wrong.

[eyl4j]

The firmware was 4.2.12 and I have now upgraded it to 4.2.30.  It looks like this took care of it... though the resync is just starting.

RAID Configuration

Configuration:	RAID Level X-RAID2, 4 disks
Status:	Resync 1% complete, Time to finish 9 hr 47 min, Speed 53.2 MB/sec

RAID Disks:

	Ch 1 : Seagate ST32000542AS [1863 GB]	1858 GB allocated
	Ch 2 : Seagate ST32000542AS [1863 GB]	1858 GB allocated
	Ch 3 : Seagate ST4000VN000-2AH166 [3726 GB]	3721 GB allocated
	Ch 4 : Seagate ST4000VN000-2AH166 [3726 GB]	3721 GB allocated

Thank you for the prompt answer.

[mdgm-ntgr]

Yes, that would be it. Support for disks larger than 2TB was added in 4.2.16.