OMV 3.X versus OMV 2.X; "Growing" a RAID 5 array

GTvert90 · Feb 1st 2019

Got it going. Thanks guys.

Yes definitely have all the important stuff backed up, like pics and documents. Most of it is media and I sync pretty regularly with a buddy.

I might step up to RAID 6 just for a little more peace of mind.

crashtest · Feb 1st 2019

Quote from ryecoaaron

There are "should"s in the statement While it should work, it may do something wrong.

The last time I looked at this, which was a couple years ago (OMV 3.X), the mdadm RAID "Grow" button added a drive as a spare. It didn't actually grow the array. There's a thread from that time frame concerning this behavior.

As of the last time I checked OMV 3, (about a year ago) the Grow button would only add a spare.

ryecoaaron · Feb 1st 2019

Quote from flmaxey

As of the last time I checked OMV 3, (about a year ago) the Grow button would only add a spare.

It adds the drive and then does two grows - https://github.com/openmediava…ned/rpc/raidmgmt.inc#L308

crashtest · Feb 1st 2019

Quote from ryecoaaron

It adds the drive and then does two grows - github.com/openmediavault/open…ned/rpc/raidmgmt.inc#L308

In OMV4, I just checked and you're right.
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But the user in this thread is still on OMV3

Quote from GTvert90

Should I reboot? I'm on OMV3.

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I have an OMV3 VM built so I checked it again. As it was before, the "Grow" button adds a drive as a spare (details below) with no option in the GUI to actually grow (as in restripe) the array.

Code

Version : 1.2
  Creation Time : Fri Feb  1 16:23:29 2019
     Raid Level : raid5
     Array Size : 10477568 (9.99 GiB 10.73 GB)
  Used Dev Size : 5238784 (5.00 GiB 5.36 GB)
   Raid Devices : 3
  Total Devices : 4
    Persistence : Superblock is persistent


    Update Time : Fri Feb  1 16:24:52 2019
          State : active
 Active Devices : 3
Working Devices : 4
 Failed Devices : 0
  Spare Devices : 1


         Layout : left-symmetric
     Chunk Size : 512K


           Name : OMV3-VM:RAID5  (local to host OMV3-VM)
           UUID : c78d3f3b:694049fe:87674a93:25445edf
         Events : 20


    Number   Major   Minor   RaidDevice State
       0       8       16        0      active sync   /dev/sdb
       1       8       32        1      active sync   /dev/sdc
       2       8       48        2      active sync   /dev/sdd


       3       8       64        -      spare   /dev/sde

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At the time (a couple years ago), I assumed that this was intended behavior - that Dev's (yourself, Volker, etc.) were attempting to discourage growing RAID5 arrays because of the risks.

ryecoaaron · Feb 2nd 2019

Quote from flmaxey

But the user in this thread is still on OMV3

OMV3 does an add then one grow - https://github.com/openmediava…ned/rpc/raidmgmt.inc#L296

Quote from flmaxey

At the time (a couple years ago), I assumed that this was intended behavior - that Dev's (yourself, Volker, etc.) were attempting to discourage growing RAID5 arrays because of the risks.

I don't think that was intentional but I honestly don't remember. Just one more reason to upgrade to OMV 4.x.

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