Post-RFS to XFS advice: shrink array, upgrade parity, AND physically reorder disks?

[JessieS]

I have a full array running 6.4.1, and have just finished RFS to XFS conversion using the mirror/preserving parity method (thank you for the great step-by-step summary!). All drives seem to be OK, with data intact. I checked parity before the reformatting process, but have not done so since.

 

1. Now, I want to remove the empty swap drive & shrink the array (using the “remove drives then rebuild parity method”). This will still leave me with a net gain of over 7TB of storage, and an empty bay for pre-clearing.

 

2. Since I'm going to rebuild parity anyway, would this be a good time to upgrade from an 8TB WD red to a 10TB HGST (NOT precleared)?

 

3. Finally, I'd like to rearrange the physical drives to help me keep them straight. When I started format conversion, my drive assignments corresponded to the physical drive slots: P,1,2,3,4,5,6,7,8 (9 empty). I added disk 9 as my swap drive, and after the conversion the drive assignments are in this physical order: P,2,4,1,5,6,7,8,9,3

 

As I understand it, unRAID matches drive assignments to serial numbers, regardless of physical drive bays. If so, can I just move them so that the assignments & slots correspond again? Before or after rebuilding parity?

 

Any caveats to the shrink array procedure if I do all three? 

 

Thank you.

[trurl]

Since you are going to rebuild parity anyway, just do New Config, assign any data drive you want to any slot you want, don't assign any drive you don't want, assign whichever parity drive you want, and rebuild parity. About the only way you can go wrong is by assigning one of your data disks to the parity slot.

[JessieS]

Thanks!

[kizer]

If I understand you correctly you asked if you could re-arrange your drives in your case. You can pretty much do whatever you want physically. Just make sure you connect your drives and assign them to whatever they was before GUI since unRAID matches serial numbers of drives to slots in the interface because if you don't you can/will loose data.  More than likely unRAID will, but never hurts to double check before you start the array. 

 

unRAID GUI

Parity- SN/990

Disk1- SN/004

Disk2- SN/002

Disk3- SN/001

Disk4- SN/003

 

Physically before the re-order which I agree would drive me a little bonkers having drives out of order. 

Disk4- SN/004

Disk2- SN/002

Disk1- SN/001

Disk3- SN/003

Parity- SN/990

 

I do mine like so physically just because my OCD says I have to. 

 

--------------Top of Case

SSD

Disk9

Disk8

.

.

.

.

Disk1

Parity

--------------Bottom of Case

 

[superloopy1]

Which if the above replies is right. Does unraid match drives to slots? I thought that was 'so 20th century'. It matches to serials now, yes? So it doesnt matter unless you are ocd conscious and 'need' them in a particular order. Why then is the parity drive an exception?

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[trurl]

19 minutes ago, superloopy1 said:

Which if the above replies is right. Does unraid match drives to slots? I thought that was 'so 20th century'. It matches to serials now, yes? So it doesnt matter unless you are ocd conscious and 'need' them in a particular order. Why then is the parity drive an exception?

 

I don't think either of the replies is wrong and they don't contradict each other in any way. unRAID does track drives by serial number. It would not be possible to even know which disk was in which bay in any case. It might be possible to track by port connection or something but serial number is the way it is done. The only point I was making about parity is don't accidentally assign a data disk to the parity slot or the data will get overwritten by parity.

 

Actually I am having a little trouble understanding your question, or possibly your misunderstanding of the replies.

 

Kizer doesn't really address all of the questions as a whole though. In addition to reordering the disks, the OP wants to remove a disk from the array and rebuild parity. A parity rebuild is required if you remove a disk (there is a more advanced method that involves clearing the disk while it is part of the array so parity is preserved).

 

New Config will let you reorder disks, remove a drive and rebuild parity all in one step. 

 

 

[trurl]

18 minutes ago, superloopy1 said:

Does unraid match drives to slots?

 

Possibly your confusion is due to the sometimes imprecise use of the word 'slot'. I use 'slot' to mean the assigned disk number in unRAID. There is also a parity slot, which if you ever read the syslog you will know is slot 0. And this usage of 'slot' is pretty common around here.

 

If I want to talk about a physical location within a case, I will use the word 'bay'. And if I want to talk about the connection, I will use the word 'port'.

 

 

[JessieS]

Thanks for the helpful discussion (sorry my terminology was imprecise/confusing).

In my rack mount case, reading left to right, I started with Parity in bay 1, then disk 1 in bay 2, and so on. Bay 10 (disk slot 9) was empty, and I added my 8TB swap drive there. The after-conversion GUI assignments are confusing to me now, so here's my plan:

 

Set the array to NOT autostart (to give me a chance to check everything before the rebuild starts when I power up).

1. Stop the array and Go to global share settings and remove the swap disk from exclude. Specify the disks to include.

2. I've created a chart so I know what drive serial numbers I want assigned to each unRAID disk slot in the GUI. That will leave me with three physical/bay changes after I power down: replace parity with a bigger drive; remove unassigned swap drive; move another drive to the empty bay (this will keep parity in bay 1, and bay 10 will be empty).

3. Stop the array (if it is started)

4. Go to Tools, then New Config

5. Click on the Retain current configuration, box (says None at first), click on the box for All, then click on close

6. Click on the box for Yes I want to do this, then click Apply then Done

7. Return to the Main page; follow my chart to unassign/reassign disks, and unassign the swap drive I want to remove.
   Question: Since the new parity disk is not yet available, do I change the Parity GUI assignment to No Device, or leave the current disk assignment?

8. Power down and make my hardware changes.

9. Power up, double-check my drive assignments.
   Question: Will I be prompted to assign the parity disk now?

10. Do not click the check box for Parity is already valid; make sure it is NOT checked; parity is not valid now and won't be until the parity build completes

11. Start the array; system is usable now, but it will take a long time rebuilding parity
     

 

[trurl]

Do the New Config after you make the hardware changes.

[kizer]

Sorry if I threw a monkey wrench into all of this. Sometimes I know what I'm talking about and assume others have super powers and can read my mind.  What I was attempting to demonstrate is you can literally swap all your drives around in your case all you want. In a normal situation all you have to do is insure the drive indicated in the GUI matches the serial number which is should before starting the array. 

 

The Term slot I said wasn't meant as a physical slot just a number on the screen and I guess it does come across confusing. 

 

However none of my rambling in the end really matters in your case since your swaping out a parity drive anyways and running a new config, but I just wanted to let you know since you asked if you can move drives around.  

[JessieS]

1 hour ago, trurl said:

Do the New Config after you make the hardware changes.

Thanks.

 

And Kizer, your comments were helpful too.

 

Thanks, all.

[superloopy1]

Thanks.
 
And Kizer, your comments were helpful too.
 
Thanks, all.

From me too.

This whole area is a confusing one. I'll take time to assimilate your reply trurl [emoji57]

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