My first time to set up the partition on multiple hard drives (SSD + HDD1 + HDD2) using RAID technology. So according my research and Debian Wiki I decide to create the following scheme:

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Where HDD2 is an external hard driver which suppose mirroring HDD1; HDD2=HDD1. So SDD and HDD1 also mirroring each other. So according to my understanding Debian Wiki the md scheme is:

enter image description here

So I'm trying to put most static files on SSD (in future adding noatime flags to make less writing on SSD) adn the rest of the system on HDD1. Which is also mirroring SSD files, in case if it failed. HDD2 is mirroring HDD1.

I'm confused with part md2=md10+SSD/partition2. How does it different from md2=HDD1/partition2 + HDD2/partition2 + SSD/partition2? Is it writing less information on SSD or I misunderstand something?

So after creating md raid partition, as I understand, I don't/need touch HDD/SSD partition now, right? I mean we work now only with md partitions, so just need to install Linux(in that case Manjaro), right?

Also HDD2 is an external drive, Do I need put any flags to active/main raid drive, after I create md(x) partition? If I unplug HDD2 and add some data, will it mirror this files on HDD1 when I plug it back?

In order to synchronize them I need to create a scheduler right? I mean if I want to sync them once a week, where I can do it (or I ned create a bash script)? And if it sync once a week automatic, but HDD2 will not be present at this time, so it will need to wait another week in order to sync, or it will sync automatically when it will plug in?

Many questions, just trying to understand how it suppose to work and how to sett this up. Thanks.

  • 1
    That’s not an answer to your question, but I think you should merge your partitions 3, 4, 7 and 8 in a single RAID array, and use LVM to split it in 4 logical volumes. You should also merge partitions 1, 5 and 6 (and possibly 2, but that’s a little more work to configure /boot in LVM). Commented Mar 23, 2017 at 22:09
  • unix.stackexchange.com/a/80868/30851 - also, don't put md on md, not sure where you even get that idea. Three way RAID-1 just works without any tricks. Commented Mar 23, 2017 at 22:33
  • @frostschutz I got this idea from dbian wiki - md1 (SSD + md10) without a bitmap to avoid SSD wear from frequent bitmap updates
    – ZeroVash
    Commented Mar 24, 2017 at 23:30

1 Answer 1


Following this article (Debian Wiki) for me it's:

  • /boot (md0) is on SSD and iHDD and eHDD (via RAID 1)
  • / (md1) is on SSD and iHDD and eHDD (via RAID 1)
  • /var (md2) is on iHDD and eHDD (via RAID 1)
  • /swap (md3) is on iHDD and eHDD (via RAID 1)
  • /home (md4) is on SSD and iHDD and eHDD (via RAID 1)
  • /mnt/work-data (md5) is on SSD and iHDD and eHDD (via RAID 1)
  • /mnt/bulk-data (md6) is on iHDD and eHDD (via RAID 1)


  1. internal SSD as SSD = /boot (md0) + / (md1) + /home (md4) + /mnt/work-data (md5)
  2. internal HDD as iHDD = /var (md2) + /swap (md3) + /mnt/bulk-data (md6) + RAID 1 of [/boot, /, /home] (md10) + RAID 1 of [/mnt/work-data] (md50)
  3. external HDD as eHDD = RAID 1 of [/var, /swap, /mnt/bulk-data] + RAID 1 of [/boot, /, /home] + RAID 1 of [/mnt/work-data]

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