TrueNAS 24 (Electric Eel) - MDADM support

TrueNAS General
1

Hi everyone,

I’m in the process of migrating my NAS to a TrueNAS install from OMV, I have a new ZFS pool created but need to connect and import data from my old MDADM RAID6 EXT4 array. MDADM seems to have been removed from this version, I found a thread of another user with similar challenge after upgrading from Dragonfish: Mdadm on Electric Eel

While long term I intend to run everything as ZFS, is there a way I can connect and migrate my existing array?

2

I ran into the same problem when I wanted to migrate from OMV to TrueNAS. I ultimately rsync’d everything over in stages because there wasn’t a clean/safe way to mount the HDDs that I was already using to migrate the data internally.

3

Thanks for confirming, I’m considering going to Dragonfish first and perform data migration (my network is just 1gbps so moving approx 30TB will take a while if not internal):

  1. Install DragonFish, create ZFS new_array
  2. Import old_array (MDADM)
  3. rysnc data from old_array → new_array
  4. verify
  5. clear old_array, re-create in ZFS
  6. Upgrade to Electric Eel down the road when needed
4

Regardless of what your network switch supports, do you have dual ethernet ports on your old and new servers and if so what are the maximum speeds of the network ports on your old and new NAS?

If you have spare ports and they are e.g. 10Gb, then you can a Cat-6 ethernet stub/1m cable to connect them directly to one another and get the full network port speeds.

I did this to move c. 8TB of data from my laptop to the new NAS - the only tricky thing was getting TN to accept a fixed IP on the second port.

1 Like
5

While I do have more ports, unfortunately they’re still 1gbps and even with bonding/aggregation I’d be leaving a lot of performance on the table.
My old array reads at about 600-700MBps and new array writes at 500MBps

6

My current plan - as I have 2 SAS controllers:

  1. Stay with Electric Eel 24.10 install with new ZFS array
  2. Install OMV in a VM and pass old_array with SAS controller passthrough (similar to my ESXi setup)
  3. Use VMNet which does not have bandwidth cap to rysnc old data over
  4. Remove OMV VM and create new 2nd RaidZ array on old_array drives