Steps to change/upgrade parity drive?

Hello all,

I'm going to apologize right off the bat for the redundant and simple nature of this question: how do I change/upgrade my parity drive? I just got a new HDD to throw in, and it's bigger than all the rest so it needs to go parity. I'm vaguely aware of what needs to be done, but I don't want to operate via trial and error on this one. Here's what I've pieced together from searches:

1) Parity check (done this, all went well)

2) Preclear new parity drive

3) Stop array, go into GUI, set existing parity to not in the array, set new parity drive as the parity drive

4) Start array, let parity rebuild

5) Preclear old drive, then stick in array when good

6) Profit?

I'm sure I missed a few steps and even more detail, but that's the knowledge I'm operating on right now. Does anyone have any suggestions, or better yet a link to some kinda of tutorial on how to do this (I couldn't find one, which I found odd)?

Thanks!

Looks good to me.

parity check after rebuild.

parity check after rebuild.

Yes, of course. Thank you for reminding me/adding that.

It's been a while since I added to the server and I'm not command line-friendly... is there any way I can pre-clear via the GUI? Or via unMENU?

There is a plugin for v6. Takes a little effort to set it up though since it still needs the script to work.

Technically, a rebuild doesn't need to be clear. unRAID only requires a clear disk when you are adding a data disk to a new slot. This is so parity will remain valid. You should test the new disk though, whether with preclear or some other method, such as the manufacturer's diagnostics.

There is a plugin for v6. Takes a little effort to set it up though since it still needs the script to work.

If ye of the 4800+ posts thinks something takes a little effort, I'm going to save myself the trouble and slog through the command line. I know my limits.

Technically, a rebuild doesn't need to be clear. unRAID only requires a clear disk when you are adding a data disk to a new slot. This is so parity will remain valid. You should test the new disk though, whether with preclear or some other method, such as the manufacturer's diagnostics.

Noted, but I'll preclear anyway. I've got the time. Better safe than sorry.

And thank you! To all involved!

Look in my sig. There is a "best practice" post on upgrading the parity drive.

QUESTION: all went well, parity upgraded with ease (even if it took ~36 hours of waiting). Do I need to preclear the old parity drive before sticking it in the array?

Look in my sig. There is a "best practice" post on upgrading the parity drive.

I actually had quite a long look at that and then formulated my own post. So many thanks.

QUESTION: all went well, parity upgraded with ease (even if it took ~36 hours of waiting). Do I need to preclear the old parity drive before sticking it in the array?

Yes you do (Assuming you mean to add it as a data drive).  If you do not then the array will be offline while unRAID clears the drive.

QUESTION: all went well, parity upgraded with ease (even if it took ~36 hours of waiting). Do I need to preclear the old parity drive before sticking it in the array?

 

Look in my sig. There is a "best practice" post on upgrading the parity drive.

 

I actually had quite a long look at that and then formulated my own post. So many thanks.

My post explained how to add the old parity without a preclear.

My post explained how to add the old parity without a preclear.

I thought I saw that, but I'm slightly confused when it comes to preclear vs. formatting. I suppose I'll give 'er a go anyway!

A SECOND QUESTION: is it possible and not inadvisable to reshuffle the order of disks? For example, my old parity was "Parity" and now it's "Disk 9". Would it be possible to stick it in at, say, "Disk 3" and bump all the other disks down? Or is this just asking for trouble?

QUESTION: all went well, parity upgraded with ease (even if it took ~36 hours of waiting). Do I need to preclear the old parity drive before sticking it in the array?

 

Look in my sig. There is a "best practice" post on upgrading the parity drive.

 

I actually had quite a long look at that and then formulated my own post. So many thanks.

 

My post explained how to add the old parity without a preclear.

Not sure how your post explains that.    I know it is not necessary to (pre)clear a disk that is to be used as parity, but it IS necessary if you want to add a disk that was previously a parity disk as an extra data disk to a parity protected array and maintain parity.  It is also not necessary at initial configuration (or after a New Config) as at the point parity is not yet active and will be calculated from the current contents of the data disks.

This is obviously different to the special case of swap-disable where you are simultaneously upgrading parity and putting parity in place of an existing disk.

A SECOND QUESTION: is it possible and not inadvisable to reshuffle the order of disks? For example, my old parity was "Parity" and now it's "Disk 9". Would it be possible to stick it in at, say, "Disk 3" and bump all the other disks down? Or is this just asking for trouble?

unRAID does not care what order the data disks are in.  In fact if you simply move them between physical connections since unRAID recognises disks by their serial number and not their port you would see no change in the order in the unRAID GUI.

If you DO want to change the order in the GUI then you would use Tools->New Config to clear the current assignments and then reassign the disks as you want them.  You can then tick the 'trust' parity option (assuming you currently have a parity disk) as the order of the data disks does not affect parity.    Make sure that you are absolutely certain which is the parity disk as assigning a data disk as a parity disk is liable to lead to data loss.

Not sure how your post explains that.    I know it is not necessary to (pre)clear a disk that is to be used as parity, but it IS necessary if you want to add a disk that was previously a parity disk as an extra data disk to a parity protected array and maintain parity.  It is also not necessary at initial configuration (or after a New Config) as at the point parity is not yet active and will be calculated from the current contents of the data disks.

 

This is obviously different to the special case of swap-disable where you are simultaneously upgrading parity and putting parity in place of an existing disk.

Did you read MY POST? "Rebuilding parity" and doing a "new config" with exactly the same data disk configuration are functionally equivalent. And if you do the new config you have the ability to assign the old parity drive to the array as a data disk before building parity, avoiding the need to preclear it. The post also makes the process as safe as possible, and enables a data disk to be rebuilt even if a disk fails during the ensuing parity build.

A SECOND QUESTION: is it possible and not inadvisable to reshuffle the order of disks? For example, my old parity was "Parity" and now it's "Disk 9". Would it be possible to stick it in at, say, "Disk 3" and bump all the other disks down? Or is this just asking for trouble?

unRAID does not care what order the data disks are in.  In fact if you simply move them between physical connections since unRAID recognises disks by their serial number and not their port you would see no change in the order in the unRAID GUI.

 

If you DO want to change the order in the GUI then you would use Tools->New Config to clear the current assignments and then reassign the disks as you want them.  You can then tick the 'trust' parity option (assuming you currently have a parity disk) as the order of the data disks does not affect parity.    Make sure that you are absolutely certain which is the parity disk as assigning a data disk as a parity disk is liable to lead to data loss.

While true, unRAID's parity protection does not care about the disk order, changing your disks around could have impacts on your user share configurations and as well as Docker or VMs configurations. While usually these impacts are small and easy to correct, you could have a few issues with the reordering.

Not sure how your post explains that.    I know it is not necessary to (pre)clear a disk that is to be used as parity, but it IS necessary if you want to add a disk that was previously a parity disk as an extra data disk to a parity protected array and maintain parity.  It is also not necessary at initial configuration (or after a New Config) as at the point parity is not yet active and will be calculated from the current contents of the data disks.

 

This is obviously different to the special case of swap-disable where you are simultaneously upgrading parity and putting parity in place of an existing disk.

 

Did you read MY POST? "Rebuilding parity" and doing a "new config" with exactly the same data disk configuration are functionally equivalent. And if you do the new config you have the ability to assign the old parity drive to the array as a data disk before building parity, avoiding the need to preclear it. The post also makes the process as safe as possible, and enables a data disk to be rebuilt even if a disk fails during the ensuing parity build.

I DID read the post.    However the OP states that he has ALREADY rebuilt parity and not yet added the old parity disk so your process does not apply.

It is of course possible to start again with your process and do a New Config and assign all disks (including the old parity disk as disk 9) and then build parity.    However that adds a period where the array is unprotected again.  It is lower risk at this point to add the disk 9 via the traditional process of pre-clearing it before adding it.  Since this is a known good disk if one uses command line options to limit the pre-clear to the writing zero phase then the elapsed time should be similar.

The OP said he read my post but seems to have missed the critical points. My comment about not needing to do a preclear is just saying if he had done it properly it should not have been needed. Maybe useful for next time. I agree that given he didn't include his old parity in the parity build he is stuck with preclearing it.

The OP said he read my post but seems to have missed the critical points. My comment about not needing to do a preclear is just saying if he had done it properly it should not have been needed. Maybe useful for next time. I agree that given he didn't include his old parity in the parity build he is stuck with preclearing it.

I did read your post but, frankly, a lot of it was above me. Rather than ask a litany of questions about every single step, I tried to piece together enough info to do it the simplest way I could. Also, I didn't like the idea of fiddling with the config directory of the USB drive. I'm sure it's all the same in the end, but to a person who doesn't know much and has enough trouble with the GUI, you're just throwing way too much on the inexperienced. So I just did what I was comfortable with, and what I could do within the GUI (save the preclear, obviously).

Regardless, everything's done now. Took a couple days of preclearing and what-have-you to get the 5TB and 4TB drives ready to go, but it's all good.

As for changing the disk order: I've decided to leave it as is. Don't want to mess with success.

Thanks for all the help!

Glad worked for you! Backing up config directory is pretty easy and gives you a recovery option if the parity build fails. I like coming up with ways to do common tasks safely and quickly, to try to help folks with unRaid. Nothing wrong with the way you did it, just took a free extra steps and 2x the wall clock time.

Enjoy your array!

Glad worked for you! Backing up config directory is pretty easy and gives you a recovery option if the parity build fails. I like coming up with ways to do common tasks safely and quickly, to try to help folks with unRaid. Nothing wrong with the way you did it, just took a free extra steps and 2x the wall clock time.

 

Enjoy your array!

It did work out, and it did take a lot of time, but I have been AFK so much the past few weeks that I barely noticed. Might look into the back up config/new config in the future to rearrange the disks if/when I upgrade parity again, but we'll see. Thanks for the help!