Issue with expanding storage in Netgear Ready NAS 4312S

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euhr wrote:

AFAICT, this should be a very straight forward thing that should work out of the box... The fact that it isn't working means that I am not doing something right or there is a software bug.

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I agree it should have worked out of the box - it could be an already-fixed bug that wasn’t listed in the release notes.

However, I don’t think it’s wise to have a single volume span both chassis.  I’d have created two volumes, one for each.

>> I agree it should have worked out of the box - it could be an already-fixed bug that wasn’t listed in the release notes.
Agreed. I will check the feasablity of upgrading the firmware to the latest version (needs a bit of downtime and I will have to co-ordinate internally for the same).
In the meanwhile, is it possible to ask internally once if this is a known issue which is fixed in the newer firmware versions?

>> However, I don’t think it’s wise to have a single volume span both chassis. I’d have created two volumes, one for each.
I can't recollect why we decided against it. Couple of things that I could think of are:

- We thought separate RAID groups would give us a bit more high availablity (and I believe we didn't have a choice to expand RAID group 1 and hence we had to go for the RAID Group 2)
- Creating new volumes would mean creating new partitions and mount them on all machines (we are still using fstab...) and its an added overhead to manage.

Any disadvantages of a single volume?

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euhr wrote:

 

Any disadvantages of a single volume?

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Though your RAID groups don't span both chassis, concatenating them into one file system increases the chance of file system corruption - because the expansion raid group can get out of step with the main chassis raid group.  Lost writes are more likely to affect multiple disks in the expansion chassis. 

For instance, lost writes to the expansion disks could be the result of

• glitches on the SAS connection between the two chassis
• power loss that hits the expansion chassis first
• failure of the expansion unit but not the main chassis
• slower write speeds on the expansion chassis, due to bandwidth limitations on the SAS connection.

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euhr wrote:

>> I agree it should have worked out of the box - it could be an already-fixed bug that wasn’t listed in the release notes.
Agreed. I will check the feasablity of upgrading the firmware to the latest version (needs a bit of downtime and I will have to co-ordinate internally for the same).

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I'd recommend waiting on mdgm-ntgr or another Netgear mod for advice on whether to do the firmware upgrade now, or whether it should wait until your expansion issue is resolved.

Noted on your points on having separate volumes.

>> I'd recommend waiting on mdgm-ntgr or another Netgear mod for advice on whether to do the firmware upgrade now, or whether it should wait until your expansion issue is resolved.
I am planning to do the upgrade tomorrow. We have to debug this further if that doesn't help.

Over the weekend, upgraded to firmware 6.9.3 after which the Expand button worked.

The data sync is in progress and hopefully everything should be good once that is done.

Thanks everyone for your help.