Removing Drives and New Config

[flambot]

I have been reading up on this part of unraid. I have never used the new config before in version 5.0 and I'd like to know what I will be presented with. Does the "New Config" link take you to another page and then allow you to do something, or does it happen as soon as you click the link?

 

I am removing 7 drives from my array. I have just about finished moving 6tb of data (it's taken days), but my next step is a new config. A which point do I disconnect the drives I am removing? Is this done "First" or do I unassign them first?

 

I am assuming a "New Config" will void the parity info. So...if the old drives are still in the array, but unassigned, does the parity sync still look at those disks or are they just sitting there being dumb as this takes place? This question is to do with the time it takes to do the sync. If I remove the disks they are out of there, but if they are still present, will the sync time be reduced because they are not included.

 

This was going to be my process...

 

1 - Take screenshot of current drive setup

2 - Power down unraid

3 - Disconnect old drives.

4 - Start Unraid (It will start in the stopped position because of missing disks)

5 - Unassign the Disks being removed

6 - Click the "New Config" link (Not sure what happens here..new page?)

7 - Parity Sync takes place.

 

I have to assume the time to assign new drive positions is after unassigning the old drives. I want to keep my drives sequentially numbered, so some of the drive positions will change. Thx

 

[trurl]

I haven't done it recently, but I think you get the main page with no drives assigned. The most important thing to remember is don't assign a data drive to the parity slot

[flambot]

I haven't done it recently, but I think you get the main page with no drives assigned. The most important thing to remember is don't assign a data drive to the parity slot

 

Yeah...that would get one excited. 

[garycase]

Clicking New Config doesn't instantly void your config => you get another page first 

 

... with a box you have to check ["Yes, I want to do this"] and an Apply button you have to click on.

 

 

 

[flambot]

Clicking New Config doesn't instantly void your config => you get another page first 

 

... with a box you have to check ["Yes, I want to do this"] and an Apply button you have to click on.

 

Thx for that - it was my expectation, but I've been caught before

 

How are the other steps? Sound about right?

When should the old drives be removed?

The parity is voided right?

[itimpi]

How are the other steps? Sound about right?

When should the old drives be removed?

The parity is voided right?

It does not really matter if you do the new config before or after the drives are removed as once it is run you are left with the 'Main' tab showing no drives assigned and the system waiting for you to assign them.  I would probably do it first as just after you have stopped the array in preparation for shutting it down.  That avoids the step of brining it up without a working configuration, but that is just my preference.

 

You are correct that the parity is invalidated.  There is a 'trust' parity checkbox but do NOT check this if you have changed any drives or you will just end up with millions of corrections when you check parity.  You will need to create new parity after you have the array drives assigned.  After that has completed you should also ideally run a non-correcting check (which should show no errors) to validate that the initial parity creation had no errors.

[flambot]

You will need to create new parity after you have the array drives assigned.  After that has completed you should also ideally run a non-correcting check (which should show no errors) to validate that the initial parity creation had no errors.

 

Why a non-correcting check? I've never really understood why (or when) this is necessary. Also, this has to be done through unMenu doesn't it?

[garycase]

The newer versions of UnRAID (v5 and v6) have the option of running non-correcting checks ...

 

... although I do NOT recommend doing that.    If there are errors, you want them corrected !!

 

The one time I make an exception to that is if you've just rebuilt a drive => in that case I'd run a non-correcting check just in case the rebuild had issues [As long as you haven't changed parity, you can re-do the rebuild].

 

[garycase]

As for your "other steps" ... here was your list of what you planned to do:

 

1 - Take screenshot of current drive setup

2 - Power down unraid

3 - Disconnect old drives.

4 - Start Unraid (It will start in the stopped position because of missing disks)

5 - Unassign the Disks being removed

6 - Click the "New Config" link (Not sure what happens here..new page?)

7 - Parity Sync takes place.

 

#1 is a good idea.  The KEY thing to know is which drive is parity and which drive(s) are cache units (if assigned)

#2, 3, 4, 5 are NOT necessary.    You can simply do #6 and set up your new configuration.    Then you can either Start the array (i.e. Step #7) and let it do the parity sync;  or you can shut it down and physically remove the drives you're not going to use anymore ... and then boot the system and do the parity sync.

 

 

[flambot]

The newer versions of UnRAID (v5 and v6) have the option of running non-correcting checks ...

 

... although I do NOT recommend doing that.    If there are errors, you want them corrected !!

 

The one time I make an exception to that is if you've just rebuilt a drive => in that case I'd run a non-correcting check just in case the rebuild had issues [As long as you haven't changed parity, you can re-do the rebuild].

Ahh...that makes sense. I've never done a non-correctly parity check (not sure you can even do this through unraid 5.0 can you?)

[flambot]

As for your "other steps" ... here was your list of what you planned to do:

 

1 - Take screenshot of current drive setup

2 - Power down unraid

3 - Disconnect old drives.

4 - Start Unraid (It will start in the stopped position because of missing disks)

5 - Unassign the Disks being removed

6 - Click the "New Config" link (Not sure what happens here..new page?)

7 - Parity Sync takes place.

 

#1 is a good idea.  The KEY thing to know is which drive is parity and which drive(s) are cache units (if assigned)

#2, 3, 4, 5 are NOT necessary.    You can simply do #6 and set up your new configuration.    Then you can either Start the array (i.e. Step #7) and let it do the parity sync;  or you can shut it down and physically remove the drives you're not going to use anymore ... and then boot the system and do the parity sync.

 

Thx. That sorts me out. I'll skip the steps you suggested, click new config, shutdown and remove the old drives. This is the most I've played with the server since I built it in 2007

 

And...as I said in another post, I'm sure the universe is messing with me. I discovered a failed drive in the system this morning (obviously failed a write while copying data across to another disk), so I'm currently rebuilding that drive. I'm a little concerned because I've just copied 5Tb of data since the last parity check. All I can hope is that it's fine. My server has been very reliable and the only 2nd failed drive ever. What did I say about computers!!  :'( Perhaps this is a good time to do a non-correcting parity check at the end of this rebuild?? If it finds an error this way, what is the procedure? I'm using my old 4Tb parity drive, which I know is good.

[garycase]

... I've never done a non-correctly parity check (not sure you can even do this through unraid 5.0 can you?)

 

Note on the Web GUI for v5 there's a box by the Parity Check (that's checked by default) that reads:  "Correct any Parity-Check errors by writing the Parity disk with corrected parity."

 

If you uncheck that box, then it runs a non-correcting check.

 

As I noted above, I NEVER do non-correcting checks except in the special case of a drive rebuild.

 

[garycase]

... the universe is messing with me. I discovered a failed drive in the system this morning (obviously failed a write while copying data across to another disk), so I'm currently rebuilding that drive. I'm a little concerned because I've just copied 5Tb of data since the last parity check. All I can hope is that it's fine. My server has been very reliable and the only 2nd failed drive ever. What did I say about computers!!  :'( Perhaps this is a good time to do a non-correcting parity check at the end of this rebuild?? If it finds an error this way, what is the procedure? I'm using my old 4Tb parity drive, which I know is good.

 

Yes, this is a good time to do a non-correcting check.    If it happens to find errors, then you have to decide if you think these were legitimate parity errors; or an error in the rebuild.    If you KNEW you had started with good parity, they would almost certainly be rebuild errors ... so you'd want to simply redo the rebuild.    Since you have some doubt; you would need to evaluate how many errors there were ... and also whether or not you have the ability to check the rebuilt disk another way [e.g. comparing the files on it against  your backups (if you have backups) or running a checksum verification (if you have checksums)].

 

Hopefully the check will simply be error-free and you won't have to contend with that 

[flambot]

Hopefully the check will simply be error-free and you won't have to contend with that 

 

Yep...lets hope so 

[flambot]

I have finally completed my server rebuild and have removed 7x data drives from the original 16. It was a major undertaking

 

Generally, the whole process went okay - and thank you very much for all the support and advice here.

 

My parity check is now taking 19 hours (a far cry from the 33 hours previously). I would like it better than this, but I have let a single drive on my TX4 expansion card until I get my next 6Tb upgrade. I'd still like to remove a couple of more drives, but that'll have to wait.

 

My upgrade included the addition of some Lian-Li Hot Swap cages, which makes changing the drives a simple process now.

 

My main concern now is a network connection issue I am trying to resolve (see another thread).

 

So thanks again 

[denizen]

I am now in the process of removing some old 1.5 TB drives which are disks 4 and 5 in my array and am planning to use the New Config option for the first time. I am planning to use the method as referenced above, but then I imagine in my case disk4 and disk5 would be missing in the new array ie disk1, disk2, disk3, disk6, disk7, etc. So here is my follow up question:

 

Once I activate the New Config option is it also possible to switch other data drives into the previously removed disk positions and keep the disk numbering contiguous? In other words, as long as I assign the correct drives for parity and cache, can I then rearrange any of the other data drives in any position I want since it is a "new config"?

[tdallen]

I am now in the process of removing some old 1.5 TB drives which are disks 4 and 5 in my array and am planning to use the New Config option for the first time. I am planning to use the method as referenced above, but then I imagine in my case disk4 and disk5 would be missing in the new array ie disk1, disk2, disk3, disk6, disk7, etc. So here is my follow up question:

 

Once I activate the New Config option is it also possible to switch other data drives into the previously removed disk positions and keep the disk numbering contiguous? In other words, as long as I assign the correct drives for parity and cache, can I then rearrange any of the other data drives in any position I want since it is a "new config"?

Yes.  After doing the new config you are brought to the main page and all drives are unassigned - as if you were booting the server for the first time.  You pick Disk 1 and then assign a drive by serial number, etc.  When you get to Disk 4 you'll just pick a drive that remains in your system.  Note that you need to refer to your drives by serial number, not sda/sdb, etc.  The sda/sdb device names will change when you disconnect some of your disks, so you need to know the serial number of the parity drive in order to reassign it correctly under the new config.  The other drive slots don't really matter, but it's critical to reassign parity correctly.

[denizen]

I am now in the process of removing some old 1.5 TB drives which are disks 4 and 5 in my array and am planning to use the New Config option for the first time. I am planning to use the method as referenced above, but then I imagine in my case disk4 and disk5 would be missing in the new array ie disk1, disk2, disk3, disk6, disk7, etc. So here is my follow up question:

 

Once I activate the New Config option is it also possible to switch other data drives into the previously removed disk positions and keep the disk numbering contiguous? In other words, as long as I assign the correct drives for parity and cache, can I then rearrange any of the other data drives in any position I want since it is a "new config"?

Yes.  After doing the new config you are brought to the main page and all drives are unassigned - as if you were booting the server for the first time.  You pick Disk 1 and then assign a drive by serial number, etc.  When you get to Disk 4 you'll just pick a drive that remains in your system.  Note that you need to refer to your drives by serial number, not sda/sdb, etc.  The sda/sdb device names will change when you disconnect some of your disks, so you need to know the serial number of the parity drive in order to reassign it correctly under the new config.  The other drive slots don't really matter, but it's critical to reassign parity correctly.

 

Then my proposed steps would be:

1 - Take screenshot of current drive setup

2 - Take the array offline

3 - Unassign Disk4 and Disk5

4 - Shut down the server

5 - Remove Disk4 and Disk5 from the server and swap Disk11 and Disk12 into these positions

6 - Start up the server

7 - Click the "New Config" link

8 - Re-assign all previous drives to their previous positions (including parity and cache) except for the drives which had been Disk11 and Disk12 which will now be assigned to Disk4 and Disk5

9 - Take the array online

10 - Watch parity rebuild

 

Does that sound reasonable? Do I need to do step 3 or just shut down the server and rearrange the drives? Also, I am assuming that invoking New Config will reset my previous share settings. Or am I incorrect in thinking this?

 

Thanks in advance!

[tdallen]

It's been a while since I removed a drive from the array, though I've done a log of New Configs (long story).  As I recall when you stop the array you can unassign a device from the disk slot - but the disk slot is still part of the array and will be emulated until you replace it.  That's not what you want.

 

Assuming that disk 4 and 5 are empty, and that your smart reports are all good (you are about to rebuild parity) you:

• Take a screenshot of current disk assignments.  Make special note of the serial number of the parity drive.
  
• Stop the array
  
• Shut down the server
  
• Physically remove disk 4 and 5
  
• Start the server but not the array
  
• Do a new config.  A new config is truly a new config - all current disk assignments will be wiped out.  You will then need to assign all disks into the array.  Make sure you assign the parity drive correctly!!
  
• Start the array
  
• Parity will be built
  

Hopefully someone who has removed a disk more recently than me will double check those steps.  I don't recall any impact to share definitions from doing a new config.

[ysss]

Is there significant change for v6?

 

Also, does clicking 'New Config' clears up the users list, shares list and other settings too?

 

Edit: Please disregard, found the answer here:

https://lime-technology.com/forum/index.php?topic=47504.msg454857#msg454857