Best pratice to replace a still working data drive with a larger one?

[trurl]

1 hour ago, jonathanm said:

you have notifications set up

I personally think that it should nag more about this. The most critical Notifications should be by email or other agent so the user doesn't have to actually remember to open the webUI to see they have a serious problem.

 

[bidmead]

Interesting question, jonathanm, but I may not be the one to answer that. I have 40 years experience as an IT journalist, but only a month's experience of UnRAID.

 

For what it's worth, it seems to me that "array turned good" was misleading once the physical drive was replaced. After all, what is the change from the previous state, emulating the missing drive, to the present state, emulating the drive but the drive is back in its slot? The goodness quotient hasn't changed: we're still emulating the drive and therefore sacrificing our insurance on all the other drives. The goodness is only restored once the physical drive has been fully successfully rebuilt.

 

This should surely be a yellow alert, saying something like: Disk 2 emulated, rebuild required.

 

Bottom line, though: the punter should alway keep an eye on the browser tab icon. If it's not a green ball, action is needed (or maybe ongoing).

 

-- 

Chris

Edited November 23, 2020 by bidmead
additional thoughts and more additional thoughts

[bidmead]

I pursued the rebuild of the Maxtor drive. But, as we might have expected, the work taxed the dear old drive beyond endurance. It failed the rebuild and UnRAID looped around several times trying the rebuild afresh until I put it out of its misery. I'm now running the rebuild on the second IronWolf Pro, which was always my original intention, to demonstrate that expanding capacity is a lot simpler with UnRAID than with, say, TrueNAS Core.

 

-- 

Chris

[trurl]

4 minutes ago, bidmead said:

demonstrate that expanding capacity

I have always preferred a small form factor so expanding capacity for me is always rebuilding to larger disks.

[bidmead]

The catch about migrating ever upwards to these very impressively engineered huge drives is that we begin to run into one of the issues that drove us away from RAID: the rebuild time and the pressure this exerts on the reliability of the other drives in the array.

 

With UnRAID, I'd have thought, much of the USP is the ability to use a large number of rather smaller drives, recovering from drive failure over a tea-break rather than during a three day vigil. And, particularly, if failing to recover, at least not losing data on the other drives of the array.

 

-- 

Chris

[trurl]

3 hours ago, bidmead said:

large number of rather smaller drives

That has even greater downsides in my opinion. Each additional disk requires more hardware to attach, more power to run, at some point more license unless you already have the Pro license. Smaller disks don't perform as well as larger simply due to data density.

 

Most importantly, each additional disk is an additional point of failure.

[bidmead]

Yes, that makes a lot of sense, trurl. Today's hard drives (especially once they've run the gauntlet of PreClear), it seems to me, are considerably more reliable than the commodity drives that inspired the invention of RAID. And even more reliable, I'd argue, than the costly enterprise drives that RAID aspired to replace. Bigger but fewer makes good sense today.

 

But I like the idea of having multiple hotswappable bays on an UnRAID system, if only because I can dump unassigned drives in there, test them with PreClear and use them experimentally as shares without having to add them to the array.

 

-- 

Chris

 

 

[bidmead]

Just to wind up the Maxstor story, I've successfully replaced that (now failed) drive with the second IronWolf Pro after a rebuild lasting one day, 10 hours, 26 minutes.

 

The Maxstor data are all preserved and the previous 300GB Maxstor share is available across the LAN. But I've hugely expanded the capacity of the array. I have my green ball back again. Job done.

 

Many thanks to this forum for the invaluable help.

 

-- 

Chris

 

[bidmead]

Actually, the Maxtor story has one last chapter. I don't know if I'm right in continuing it here because it raises a rather different issue. But let's see.

 

The old Maxtor failed the rebuild, almost certainly due to a bad sector or sectors. However, I understand that the PreClear app can reallocate dud sectors, so I ran the drive through another single-pass total preclear. It passed.

 

So I've now set it up as I originally intended: it's a luks-btrfs unassigned drive exported as a disk share. It doesn't turn up under Main/Disk Share, I assume because it's not exported from the array. (Is this right?)

 

The luks-btrfs format was created against a pass phrase which will be required every time the disk is mounted. You can set this drive to auto mount or mount it manually from the WebGUI. To do either of these you need (only once) to enter the pass phrase into Setting/Unassigned Devices/Set Encrypted Disk Password.

 

Now the share can be loaded with no formality across the LAN. But this isn't, of course, very secure. You really want the share only able to be loaded against a pass phrase. But you can't share the disk until its mounted. And you can't mount it without the pass phrase. So, by definition, once it's a share its not password protected (except against it being stolen, with data access attempted outside the UnRAID device).

 

Is this how it is, or am I missing something?  (I feel I probably am.) If not, then the workaround is clearly to use something like VeraCrypt to create an encrypted disk image on an unencrypted share or drive and require Veracrypt on the client device for the decryption.

 

-- 

Chris

 

 

[bidmead]

It seems that unassigned drive encryption has developed since this video from SpaceInvader One. The password's no longer in plain text in a file called keyfile. It's now encrypted in  /tmp/unassigned.devices/config/unassigned.devices.cfg. And despite being in /tmp, as far as I can make out the file persists through powercycles. So the data will remain encrypted if someone steals the drive but will autodecrypt if the whole UnRAID server is stolen.

 

Have I got that right?

 

-- 

Chris

[shEiD]

On 11/23/2020 at 7:36 AM, bidmead said:

 

@bidmead Awesome looking annotations 🤩 What program are you using to do this?

[bidmead]

It's for creating comics. An Android app called PicSay. Very easy and useful. I use it quite a bit.

 

-- 

Chris