[SOLVED] Question about starting over 100TB Unraid server


rmilyard

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I have a UnRaid 6.6.6 server that I have been having some issues with.  I would like to know if I can just start over?  I have 14 data drives and 2 parity.  I added along the way and didn't know when first started that would make things easier is added drives in order.  I just added them and used drop down. 

 

My case has 16 bays but my drives # don't match.  I would like to get it all matching now.  So start with Data 1-14 in each slot and add the 2 parity in last slots in case.

 

I am not sure if this is something I can do.  I don't want to copy 60tb of data to something else.  Also at the moment I don't have extra storage laying around to use for this.

Edited by rmilyard
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It sounds like all you have to do is rebuild parity once you have established which drives are your parity drives.  To me at least.  You might see if more people agree with my opinion.

 

I have done this (rebuild my parity) many times.  I have done it when I have had to move around a lot of data to get it organized the way I want it or rearrange my disks in a 2 parity system.  I just disk connect parity drive 2 (or both if I'm actually moving data and not just disks) then rebuild parity by adding back my parity drives.

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Just not sure how to go about this.  All my slots in server have drives.  Not sure how can do this without losing data etc.  I am rebuilding parity right now as I type for next day.

 

So right now my 2 parity drives are in slot 1 and 2 of server case.  I was going to move them to 15 and 16.  Then get my others to line up so Disk 1 in Unraid would match to slot 1 in case.

Capture2.png

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Its not really hard.

  1. make a printout / copy of this snapshot on a standalone system like a phone or laptop
  2. Power down if you need to see the drive's serial# to label them.
  3. Label the physical drives against the snapshot (matching the screen shot)
    • Disk #1 -> Toshiba #1
    • Disk #2 -> Toshiba #2,, etc.
    • etc
  4. Move the disks as you like into the physical slots (Drive#1 -> slot#1, etc)
  5. Poweron Unraid.
  6. Done

Unraid recognizes by serial number, so moving disks around by the slot, connecting cable should not change with how the disk is recognized.

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Parity 1 will always valid even disk order change, only parity 2 need rebuild. I would suggest make array from 2 parity to 1 parity and then rearrange slot and add back parity 2 as usual.

 

2 advantage

- Keep parity 1 haven't write

- During rebuild parity 2, all other disk can be spin down

Edited by Benson
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9 minutes ago, Benson said:

Parity 1 will always valid even disk order change, only parity 2 need rebuild. I would suggest make array from 2 parity to 1 parity and then rearrange slot and add back parity 2 as usual.

 

2 advantage

- Keep parity 1 haven't write

- During rebuild parity 2, all other disk can be spin down

What do you mean by that last statement? Parity2 calculates from the array disks, not Parity1.

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10 minutes ago, jonathanm said:

What do you mean by that last statement? Parity2 calculates from the array disks, not Parity1.

Yes, parity 2 was calculates from all other disk. But if in add back operation, i.e. from 1 parity array to 2 parity array, then all other disk no need read and calculate.

Edited by Benson
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5 minutes ago, Benson said:

Yes, parity 2 was calculates from all other disk. But if in add back operation, i.e. from 1 parity array to 2 parity array, then all other disk no need read and calculate.

This isn't any clearer I'm afraid. There isn't any way to build parity2 without reading all the data disks. It cannot be derived from parity1.

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Just now, trurl said:

This isn't any clearer I'm afraid. There isn't any way to build parity2 without reading all the data disks. It cannot be derived from parity1.

The reason I can't fully explain ( I am not fully know parity 2 how to calculate ), but above was I got when I do this operation. Hope I haven't remember wrong.

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There should be no need to drop to 1 parity drive.

In Unraid physical slots != logical slot

I have a HBA + enclosure with 8 drive slots and My Motherboard has 6 SATA ports + 1 M.2 socket.

When I added a M.2 SATA SDD, it became physical slot 1, with higher priority than my old Intel M-25 SSD (which used to be physical slot 1)

When I upgrade/upsize HDDs, I typically add into physical slot 7 of my enclosure, then stop the array, replace whichever drive, with the new one, without doing any physical movements. When the drive has been rebuilt and I'm happy with it, I stop the array, remove the replaced drive, and move the new drive to the physical slot of the just removed drive. (All hotplugged, as the enclosure supports hotplugging and the array is stopped) Then I start the array, no need to fiddle with any settings.

My advice above is for people who have a lot of disks and need to powerdown to move disks around (instead of hotplugging)

If you have hot plugging, you can stop the array, and while you have the disk assignments screen open:

  1. pull out array disk 1 - you'll see disk #1 in the screen become marked as missing
  2. pull out disk in physical slot/bay 1 and swap with disk#1 -both disks will then appear in their original logical slots.
  3. repeat for all the drives - until all the drives are in the bays you want them to be in.
  4. start the array

There. done. 

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8 minutes ago, ken-ji said:

There should be no need to drop to 1 parity drive.

In Unraid physical slots != logical slot

I have a HBA + enclosure with 8 drive slots and My Motherboard has 6 SATA ports + 1 M.2 socket.

When I added a M.2 SATA SDD, it became physical slot 1, with higher priority than my old Intel M-25 SSD (which used to be physical slot 1)

When I upgrade/upsize HDDs, I typically add into physical slot 7 of my enclosure, then stop the array, replace whichever drive, with the new one, without doing any physical movements. When the drive has been rebuilt and I'm happy with it, I stop the array, remove the replaced drive, and move the new drive to the physical slot of the just removed drive. (All hotplugged, as the enclosure supports hotplugging and the array is stopped) Then I start the array, no need to fiddle with any settings.

My advice above is for people who have a lot of disks and need to powerdown to move disks around (instead of hotplugging)

If you have hot plugging, you can stop the array, and while you have the disk assignments screen open:

  1. pull out array disk 1 - you'll see disk #1 in the screen become marked as missing
  2. pull out disk in physical slot/bay 1 and swap with disk#1 -both disks will then appear in their original logical slots.
  3. repeat for all the drives - until all the drives are in the bays you want them to be in.
  4. start the array

There. done. 

I think OP also want sd'x' in order, all physical slot and logical slot also match order.

Edited by Benson
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5 minutes ago, Benson said:

I think OP also want sd'x' in order, all physical slot and logical slot also match order.

Also there is no way to make sd'x' assignments stick. if the usb decides to boot a little slower, it may switch sd'x' smack in the middle of the pool.

3 minutes ago, rmilyard said:

That would be nice all. But trying to make easier so when say disk 5 fails I can go to server and know slot 5 is disk 5. 

yes. for a lot of drives its better to know which physical slot/bay is which disk so its easier to replace. I maintain mine in relative order so it will make replacing easier later on. particularly if you have a headless server.

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If all you want is to move the disks in the case but don't need to change the actual disk (serial number) assigned in the webUI then just move them in the case. Unraid doesn't care, it only looks at the serial number to keep them assigned correctly.

 

I usually use the word "bay" to refer to a location in the case, the word "port" to refer to the connection, and the word "slot" to refer to how they are assigned in Unraid. If you ever take a look at your syslog you will see Unraid listing the assigned disk inventory by their "slot".

 

1 minute ago, Benson said:

I think OP also want sd'x' in order, all physical slot and logical slot also match order.

Now you've done it. You dragged sd'x' into the discussion, which is totally irrelevant and not even guaranteed to be consistent from one boot to the next. It is the md# that corresponds to a specific disk serial number.

 

Also, the very reason you have to rebuild parity2 if you change the disk order is because it must be calculated from the disks themselves in the order they are assigned. If it can be calculated from parity1 alone then how could the order possibly matter?

 

Sorry OP if this has gotten confusing. Just move them to whichever "bay" you want and forget about it. Unraid won't care if you don't change the actual disk (serial number) assigned to each "slot" in the webUI.

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Well thanks all for the info. I dropped to 1 parity drive for now since had to replace parity 2 drive due to failure. 

 

So after rebuild tomorrow I should be able to shut down array and move my parity 1 to bay 15. I’ll use bay 16 for parity 2. 

 

Then move over all my other drive around so disk 1 will match up with drive in bay 1 and so on and on...

 

?

Edited by rmilyard
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20 minutes ago, rmilyard said:

What is command to do this?  xfs_repair /dev/sde  

 

what flags do I need?

No repairing the sd device would invalidate parity, and you left off the partition number anyway. You have to repair the md device to maintain parity.

 

Just use the webUI, start in Maintenance Mode, then click on the disk to get to its page.

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