Adding a disk to ReadyNAS Pro for RAID5/6 volume expansion?

On 4.2.16 (due for a production release soon), there is an option you can select (under Volumes > Volume Settings > RAID Settings) before adding a disk to an empty drive bay to migrate from X-RAID2 single-redundancy (like RAID-5) dual-redundancy to X-RAID2 dual-redundancy.

I don't know if you can do similar with Flex-RAID. You can however expand Flex-RAID volumes on 4.2.16 as indicated here: http://www.readynas.com/forum/viewtopic.php?p=279423#p279423

mdgm wrote:
On 4.2.16 (due for a production release soon), ... I don't know if you can do similar with Flex-RAID. You can however expand Flex-RAID volumes on 4.2.16 as indicated here: http://www.readynas.com/forum/viewtopic.php?p=279423#p279423

that would be exactly my case:

Horizontal Expansion: only RAID5 and RAID6 as you are adding next disk into current RAID array.

so the answer is to wait for the 4.2.16 release?
If I add the disk as a hot spare now, would I still be able to use it to extend the volume later on, or should I wait?

I'm not sure of the answer to this question. 4.2.16 is due very soon so I'd be inclined to wait.

chirpa wrote:
http://www.readynas.com/RAIDiator_x86_4_2_16_Notes

OK, it almost worked. I upgraded to 4.2.16 and then the volume tabs for both of my volumes had a section listing the new disk 5, and a new checkbox to add it to the volume. I actived the one for Volume C (RAID6), and before rebooting, had a look at the tab for Volume D. The checkbox was grayed out, so I thought I had to do the expansion one after the other.

After the reboot Volume C was successfully expanded to span all 5 disks. But now the tab for Volume D no longer had the section listing the new disk 5, and no chance to add anything to it.

I had a look at the logs. The partition tables for disks 1-4 have:

Number  Start (sector)    End (sector)  Size       Code  Name
   1               4         8388611   4.0 GiB     FD00  Linux RAID
   2         8388612         9437187   512.0 MiB   FD00  Linux RAID
   3         9437188       442189827   206.4 GiB   FD00  Linux RAID
   4       442189828      3907026947   1.6 TiB     FD00  Linux RAID

and disk 5 has:

Number  Start (sector)    End (sector)  Size       Code  Name
   1              64         8388671   4.0 GiB     FD00  Linux RAID
   2         8388672         9437247   512.0 MiB   FD00  Linux RAID
   3         9437248       442189887   206.4 GiB   FD00  

so there is a slight difference, but still room for that extra partition to add to Volume D, but how can I tell it do to so? :(

Disk 5's partitions are 4k sector aligned. The rest are not.

I don't know if this will solve your expansion issue but I'd suggest doing the following:

1. Wait for the expansion of Volume C to complete (if it hasn't already)
2. Hot-remove (remove while NAS is on) disk 1.' wait a minute or so then hot-add the disk.
3. Wait for the resync to complete then repeat the process for disks 2, 3 and 4 waiting for the resync to complete before moving onto the next disk.

mdgm wrote:
Disk 5's partitions are 4k sector aligned. The rest are not.

this is probably caused by the fact that the original disks were formatted under an earlier FW version, and disk 5 was formatter under 4.2.15 (before I upgraded to 4.2.16), and alignment seems to have changed.
But there is still enough room. Partition 4 is 3464837120 sectors, and the geometry of disk 5 is

Disk /dev/sde: 3907029168 sectors, 1.8 TiB
Logical sector size: 512 bytes
...
First usable sector is 34, last usable sector is 3907029134
Partitions will be aligned on 64-sector boundaries
Total free space is 3464839277 sectors (1.6 TiB)

mdgm wrote:
1. Wait for the expansion of Volume C to complete (if it hasn't already) 2. Hot-remove (remove while NAS is on) disk 1.' wait a minute or so then hot-add the disk. 3. Wait for the resync to complete then repeat the process for disks 2, 3 and 4 waiting for the resync to complete before moving onto the next disk.

I'd have to be certain that after this open heart surgery, it will allow me to expand Volume D.
There is quite a bit of useful stuff in the expansion.log on how Vol C was extendended, so I am tempted to gain ssh access and perform the same procedure for Vol D. I am worried about the consistency of the FrontView data, though.
I hope there is an easier method.

Can anyone from ReadyNAS please confirm that the suggested method (pull out one disk after another), which I consider a bit dangerous, will indeed solve the problem so that I can extend both volumes to include the new disk, or suggest an alternative?
I just updated to 4.2.17 and there still is no button that would allow me to extend volume D.

Roman

Ok, I went ahead and, one by one, removed and reinserted the four original disks. Each time the two volumes present were properly rebuilt, and all partition tables now start at sector 64.
Nevertheless, I still cannot add the free space on the new disk 5 to the second volume. The partition tables of the old and new disks are identical,
Disks 1-4:

First usable sector is 34, last usable sector is 3907029134
Partitions will be aligned on 64-sector boundaries
Total free space is 2157 sectors (1.1 MiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1              64         8388671   4.0 GiB     FD00  
   2         8388672         9437247   512.0 MiB   FD00  
   3         9437248       442189887   206.4 GiB   FD00  
   4       442189888      3907027007   1.6 TiB     FD00  

Disk 5:

First usable sector is 34, last usable sector is 3907029134
Partitions will be aligned on 64-sector boundaries
Total free space is 3464839277 sectors (1.6 TiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1              64         8388671   4.0 GiB     FD00  
   2         8388672         9437247   512.0 MiB   FD00  
   3         9437248       442189887   206.4 GiB   FD00  

When I remove and reinsert the new disk 5, which is part of volume C, but not D, volume C is correctly rebuilt, and during that time, there is a grayed-out option in the tab for volume D to add this disk.
But: after rebuilding C finishes, this option is no longer there :(
The tab to create a new volume also shows available space on disk 5, but I can't figure out how to add it to an existing volume.

So, how can I convince Raidiator to reconsider this disk as 'new', and use its free space?

Has anyone else tried to add a new disk to a system with two RAID5/6 volumes, and it worked?

As a second-to-last resort, I might delete the second volume, then hope that I can recreate it using all five disks.

Roman

With the help of Netgear technical support, the issue was resolved. The engineer ended up accessing my unit with ssh and manually added a partition of the new disk to the second volume. It seems to be a flaw in Raidiator that it does not allow to extend systems with two volumes.