ReadyNAS 104 4x4TB drives RAID 5 gives less than 8TB for a LUN?

[Deaton64]

Hello,

I have a brand new ReadyNAS 104, firmware 6.4.0. I installed 4 x WD Red 4TB drives. Created a RAID 5 volume that took 4 days to sysnc. Half way through the sync, I tried to create a LUN, but that didn't seem to work, so I waited for the sync to end.

A new RAID 5 volume gives me a 10.90TB volume. On that volume, if I try to create a new LUN, even though it states "Maximum Size: 10045.946 GB (90% of free space)" can be created, the largest I can create is 7.9TB. That's 50% of my drives!

Any ideas why?

If I try to create anything more than 8TB, I get "21001019744 Error creating LUN backing store".

I don't want any snapshots, I just want as much space as possible that I can squeeze out of the disks I have in RAID 5.

Thanks for any help,

David

[StephenB · Accepted solution]

The release notes capture this limitation ( http://kb.netgear.com/app/answers/detail/a_id/29938/~/readynas-os-version-6.4.0 )

ReadyNAS 102, 104, and 2120 only support creating iSCSI LUNs 8TB and smaller.

Why do you need everything in a single LUN (instead of using shares)?

[StephenB · Accepted solution]

The release notes capture this limitation ( http://kb.netgear.com/app/answers/detail/a_id/29938/~/readynas-os-version-6.4.0 )

ReadyNAS 102, 104, and 2120 only support creating iSCSI LUNs 8TB and smaller.

Why do you need everything in a single LUN (instead of using shares)?

[Deaton64]

Hello,

Thanks for that.

I want to use as much space as possible to attach via iSCSI to a HP Microserver. The space is going to be used for Veeam backups. Each backup file is approx. 1TB.
Maybe I can do it with shares, but Veeam needs to see the drive it writes to as directly attached storage.

David

[StephenB]

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@Deaton64 wrote:

....Veeam needs to see the drive it writes to as directly attached storage.

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Sounds like you do need iSCSI then.  Can you set up multiple targets? (that is, use 2 LUNs)?

[Deaton64]

Hi,

I don't know. I'll give it a go, or it will have to be a new NAS 😞

Thanks for your help,

David