Hot swap question

[JorgeB]

... although I wouldn't want to do it on a disk that was part of a mounted array.      Not sure whether or not Linux would warn you in the case or not -- kind of like Windows will refuse to "safely remove" a drive that's actively in use (e.g. your C: drive).  But it should work fine as long as you Stop the array first.

 

Tried it on an array disk:

 

Jan 13 17:09:26 Tower8 kernel: sd 8:0:0:0: [sdg] Synchronizing SCSI cache
Jan 13 17:09:26 Tower8 kernel: sd 8:0:0:0: [sdg] Stopping disk
Jan 13 17:09:27 Tower8 kernel: ata8.00: disabled
Jan 13 17:09:36 Tower8 kernel: md: disk3 read error, sector=244317864
Jan 13 17:09:36 Tower8 kernel: md: disk3 write error, sector=244317864

 

Disk was disabled, so if this is used it must be done with care.

 

Now let me rebuild that disk 

[RobJ]

Now let me rebuild that disk 

 

You've been awarded an unRAID Purple Heart!

[lionelhutz]

My bays have power buttons and I don't see any reason to be concerned about swapping disks if they are not mounted.

[garycase]

... although I wouldn't want to do it on a disk that was part of a mounted array.      Not sure whether or not Linux would warn you in the case or not -- kind of like Windows will refuse to "safely remove" a drive that's actively in use (e.g. your C: drive).  But it should work fine as long as you Stop the array first.

 

Tried it on an array disk:

 

Jan 13 17:09:26 Tower8 kernel: sd 8:0:0:0: [sdg] Synchronizing SCSI cache
Jan 13 17:09:26 Tower8 kernel: sd 8:0:0:0: [sdg] Stopping disk
Jan 13 17:09:27 Tower8 kernel: ata8.00: disabled
Jan 13 17:09:36 Tower8 kernel: md: disk3 read error, sector=244317864
Jan 13 17:09:36 Tower8 kernel: md: disk3 write error, sector=244317864

 

Disk was disabled, so if this is used it must be done with care.

 

Now let me rebuild that disk 

 

Agree with Rob => You deserve an "UnRAID Purple Heart".    Gutsy to try that on an array disk ... although I suspect this was on your all-SSD test array -- which we all REALLY appreciate you having, as it allows a LOT of testing that otherwise likely wouldn't get done.

 

[JorgeB]

Agree with Rob => You deserve an "UnRAID Purple Heart".    Gutsy to try that on an array disk ... although I suspect this was on your all-SSD test array -- which we all REALLY appreciate you having, as it allows a LOT of testing that otherwise likely wouldn't get done.

 

Actuality it was my work server, if I was home I would do it on the test server, I was expecting some "disk is being used" error, but rebuild was successful, no harm done 

[garycase]

Agree with Rob => You deserve an "UnRAID Purple Heart".    Gutsy to try that on an array disk ... although I suspect this was on your all-SSD test array -- which we all REALLY appreciate you having, as it allows a LOT of testing that otherwise likely wouldn't get done.

 

Actuality it was my work server, if I was home I would do it on the test server, I was expecting some "disk is being used" error, but rebuild was successful, no harm done 

 

Definitely gutsy !!  And worth a couple purple hearts !!  :)

 

I'd have also expected a "disk is being used" error (ala Windows) ... but clearly it just does what you tell it to and the consequences be damned.    Fortunately it's a fault tolerant server -- so as you noted, you just have to rebuild the disabled disk.

 

[Can0n]

I have done this using my i7 server in my signature more than a few times to upgrade disk sizes and replace failing drives my server is chock full of 5/6 and 8TB drives with two 1TB SSD sitting between the motherboard and fan wall. just replaced one tonight and unraid wouldnt see the new drive at all until i rebooted. this is first time it did that it usually detects the replacement drive and when i start the array it starts rebuild.....approx 17hrs for 8TB drive to rebuild

[ridley]

I have just tried hot swapping, stopped the array, installed disks and restarted. Disks were picked up in UnAssigned devices before I got back to my PC. 

 

However I was not able to delete the partitions using UnAssigned devices on those drives until I rebooted.

[miicar]

Just to flog an old horse, i just did a fun one! 

 

After losing a couple pools due to drive swapping issues, I have found that managing cache pools is much faster (and safer) with CLI.  So to learn this better, i decided to toss a bunch of drives into a drive enclosure and play with a non-critical pool; adding, replacing, and removing disks over a week period!  I did all this remotely, without ever stopping the array!!  From plugging the e-SAS into the drive enclosure, inserting the drives, and running the various commands i was looking to learn, everything was done "hot"!  (the rest of the server is used in production so it couldn't be stopped)! 

So what happened??  Well, as expected, the GUI didn't update the new pool drive assignments as i was moving things around via CLI!  The old drives were still showing in the pool but spun down.  And the new, actively running, drives were still in Unassigned Devices area (with the "mount" button greyed out...might have said "pool" instead. I should have saved the screenshots.).   But of course the CLI showed the correct information and my operations were working great! 

Once i was done everything i wanted to try, and it was ok to take the server offline, i took a screenshot of the most recent, CLI-derived, drive assignments for that pool and stopped the array.  Then changed those drive assignments in the GUI to match the CLI, and hit start!  Everything worked and all is well!  And just to add to the fun, it's the ill fated BTRFS RAID5!  hehe🤪

Was it confusing?  Definitely!!!  I had to be super careful to keep everything organized and not f-up an active drive...10/10 would not suggest!!  BUT, at your own risk, it is possible to manage pools, hot swap new/old disks while the array is happily running IF YOU ARE SUPER CAREFUL AND KEEP DETAILED NOTES AS YOU ARE MANAGING THINGS!!  (and if your hardware supports hot swapping of course)  

 

I haven't tried anything with the array itself while its still running...my guess is that would not be possible and you would probably break allot of things if you tried...but maybe one day i'll fire up my OG unraid ddr2 P3 mobo together and test it!  

Edited December 1, 2023 by miicar
spelling and grandma