Home / server / Questions / 1031049
In Process
Crash Override
Asked: 2020-08-22 19:23:48 +0800 CST

Can I Move RAID-1 (Mirrored) Hard Drives From a Hardware Raid Controller to Software Raid?

  • 772

Old server:

  • 3ware 9650se PCIe hardware RAID controller with 2 sets of RAID-1 (4 total drives, 2 mirrored) with a 5th drive as a hot-spare.

New server:

  • Software RAID is the only option. Plan to run linux mdadm with the same RAID-1 configurations.

These are not boot drives, storing just data.

Can I transfer the drives from hardware RAID to software RAID? Will the data be intact?

raid hardware-raid raid1

2 Answers

  1. Linux Software RAID (md) has a support for some of hardware RAIDs superblocks, man mdadm:

    -e ddf    Use  the  "Industry Standard" DDF (Disk Data Format) format defined by SNIA.

    If 3ware's metadata format is not supported when you plug the disks into usual SATA ports all data they have should be accessible to the system.

    Since it's RAID-1 you aren't at a huge risk when trying but the real safe side is having backups first anyways.

    A few different RAID-1 "jumpstart procedures" can be applied:

    1. you create an md device using a single disk and empty another — that would give you LSR superblock applied then you could just add the second disk onto "empty" slot.
    2. Or, you could start basically with both disks at once using --assume-clean when creating it.

    Middle risk approach is using 3 disks for this procedure — if you have a 3rd blank one just use it for procedure 1 adding second disk. That way you always have a full copy of your data on second replica of HW RAID array which isn't touched by any operation.

    • 3

  2. No, you would have to transfer/copy/backup data from your HW RAID volume and then move it to your software RAID volume.

    Duplicate of https://unix.stackexchange.com/questions/46381/migrating-from-hardware-to-software-raid

    • -2