T14:How Does One Migrate to Dual Redundancy

[bollar]

I can't find the migration path for dual redundancy in Frontview or RAIDar. What am I missing?

[Ki-Adi-Mundi]

Do you have a xraid2 ? And what kind of model do you have , Pro ? How many disks in you machine now ?

[bollar]

ReadyNAS Pro Business, xraid-2, six drives.

[Ki-Adi-Mundi]

it can't be done for this condition, because you have all your six disks in , so there are no extra disks can be used to migrate to dual redundancy, you need have at least one free disk channel to do this. Now we do the migrate option for newly added disks.

[TeknoJnky]

how does the migrate option work for new drives, doesn't the nas automatically add the new drive and start expansion?

[Jedi Knight]

TeknoJnky ,

For example, you have 3 disks XRAID2 volume. You will be presented with an option to either Migrate or Expansion for next disk add. Base on the setting in frontview, the next added disk will perform migration or expansion. In order to expand, all the XRAID2 layers must have at least 3 Disks.

[TeknoJnky]

ok I see, so option must be set in frontview before adding disk, good to know

[danky]

I have 4.2.16-T75, ReadyNAS Pro X-RAID2 with 5 disks.

Where should appear the option for switch to dual redundancy in next disk? I see nothing in Volume settings.

Thanks.

[danky]

More info about my configuration: I have 3x0.5TB and 2x1.5TB disks.

I want to put a 2TB disk in the sixth bay for dual redundancy, and later I will change a 0.5TB with another 2TB disk.

Is that ok?

[mdgm]

If it's there, it should show under Volumes > Volume Settings > RAID Settings tab. See if there's a scroll bar for the tab. Maybe you need to scroll down?

There are a few other possibilities, I guess:

1. You have a dual-layer array. Dual-redundancy is limited to using the capacity of the fourth largest disk on any given disk (unless the capacity of the disk in question is smaller of course). It's likely you need to replace one of the existing 500GB disks with a 1.5TB (or greater) capacity disk before you can see the option to make the next disk you add migrate you to dual-redundancy. Due to the nature of X-RAID2 (eXpandable not shrinkable RAID) a move to dual-redundancy cannot involve the shrinking of the size of your volume.
2. Have you checked to make sure your disks' partitions are 4k sector aligned?

[danky]

How I can check if they are 4k sector aligned?

An fdisk -l shows:
1 4 8388611 8192K 0700 Linux RAID
2 8388612 9437187 1024K 0700 Linux RAID
5 9437189 976768064 922M 0700 Linux RAID
In the three 0.5TB disks and:
1 4 8388611 8192K 0700 Linux RAID
2 8388612 9437187 1024K 0700 Linux RAID
5 9437189 976768064 922M 0700 Linux RAID
6 976768065 2930272064 1863M 0700 Linux RAID

In the two 1.5TB disks. I suppose they are 4k aligned.

I suppose that the problem is because the dual-layer so I need another 1.5TB as you said.
I will do that.

Thanks.

[mdgm]

You're looking for the starting sectors being divisible by 8.

I'm not sure what the SSH way to check this is (the output in the logs appears to be different in 4.2.16 so I'm not sure if the SSH command needed has changed). Simplest thing to do would be to go to Status > Logs > Download all logs > extract zip contents and look in partition.log

If a disk is 4k sector aligned you should see something similar to this:

Code: Select all

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
   5         9437256      2930272064   1.4 TiB     FD00  Linux RAID


I'm not sure if not having 4k sector alignment prevents a migration to dual-redundancy, but as it can be an issue for expanding your volume, I'm guessing there's a fair chance it could be.

As I mentioned in my post above there will still be a need to replace one of the 500GB disks with a 1.5TB (or greater capacity disk), wait for the resync to complete then select the option in Frontview to migrate to dual-redundancy then add another high capacity disk.

If you replace one 500GB disk with a 2TB disk, 1.5TB will be utilised (cannot expand using single-redundancy unless redundant space can be added) so that may be O.K. I'm just guessing as I haven't done this myself.

[danky]

Is the same output as fdisk -l from ssh

The start sectors of first partition in all disks is 4, so that is not divisible by 8.
The rest of the partition starts are also not divisible by 8.

I can backup all data and start from zero, maybe is the best for have DR from start and 8k aligned sectors, right?

I would use this setup: 2x0.5TB, 2x1.5TB, 2x2TB
So I guess I will have 4TB until i change the 0.5TB with 2TB disks

[mdgm]

Is the same output as fdisk -l from ssh

Thanks.

I can backup all data and start from zero, maybe is the best for have DR from start and 8k aligned sectors, right?

Probably would be a good idea if you have the time. You'll need 4k sector alignment eventually anyway (even if not choosing 4k sector 2TB disks now) and a backup and factory default may well be quicker. It'll also give you a clean setup on the latest firmware. If you look in initrd.log and see that you last factory defaulted before 4.2.11, then the move to native EXT4 from a factory default (on 4.2.11 or later - obviously you'd stay on the 4.2.16 beta firmware or use the production firmware if that is available by the time you wish to do the factory default) is a nice bonus. Native EXT4 allows for file sizes greater than 2TB, with a limit of 16TB. It has other nice benefits too.

You may wish to do a System > Config Backup (keep zip file) before the factory default, then restore the Config Backup (zip file that was downloaded) afterwards.

I would use this setup: 2x0.5TB, 2x1.5TB, 2x2TB
So I guess I will have 4TB until i change the 0.5TB with 2TB disks

Yes, before overheads and also allowing for disk manufacturers considering 1 KB = 1000 Bytes, whereas NAS (like most other computers) considers 1 KB = 1024 Bytes. You would only need to change one of the 0.5TB disks with a 2TB disk to expand your volume (another edit: it would of course be treated as a 1.5TB disk until you had a fourth 2TB disk in your array).

Edit: One should note that to get 4k sector alignment you can swap hot-remove one disk, then hot-add it and wait for the resync then repeat for the next disk. This is very time consuming (more so than a factory default) and shouldn't be attempted if you don't have a good backup. Also as I said earlier I don't know if 4k sector alignment is required or not for a migration to dual-redundancy.