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Currently , on the laboratory I'm working on, there are three NAS:

  • 2x Seagate NAS Pro with 15TB (RAID 5)
  • 1x FreeNAS machine with 9TB (RAID 0)

All of these are used through NFS shares mounted on different paths but IMHO that's far from ideal. We're going through an expansion soon and will need more storage. I needed some kind of mechanism for "merging" those NASes together so I could optimize the use of disks still providing space for larger datasets.

One of the data centers I use has an AFS share that seems really nice, but I don't really understand much about file systems and don't know if that's the way. I've searched about mergerfs, aufs, OverlayFS, mhddfs and many other stuff but I can't find an optimal solution for me and have no idea of where to look for it.

Can you guys please help me on that?

Gabriel Milan
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  • What do you mean by merge? What does the optimal result look like? – Eduardo Trápani Jun 28 '20 at 19:50
  • AFS won’t help you merge two NASs anyway. You need to run a custom server and client to provide access to the data in AFS, and you can’t re-export existing data. – jsbillings Jun 28 '20 at 20:44
  • Do you need a bind mount on top of the NFS shares? Not sure if I understand the question... – dirkt Jun 28 '20 at 21:53
  • @EduardoTrápani something like a "RAID 0" for the NASes. I want them to be seen as a single share with, for example, 39TB (2x 15TB + 9TB, as described above) – Gabriel Milan Jun 28 '20 at 22:45
  • @jsbillings thanks for replying, I just thought about AFS because I've seen it before, I don't really know how it works – Gabriel Milan Jun 28 '20 at 22:46
  • @dirkt I'm not really sure that's necessary. Currently, a NFS share that we use for the $HOME directories is mounted on my nodes with nas.example.com:/mnt/path/home /home nfs rsize=32768,wsize=32768,bg,sync,nolock 0 0 and works fine for our purposes – Gabriel Milan Jun 28 '20 at 22:48

1 Answers1

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You can export raw iSCSI volumes from one of the NAS servers and build a volume on the other one, with the local disks and the remote iSCSI volumes.

  • NAS1 exports its disks via volumes over iSCSI

  • NAS2 imports those disks, adds them to its own local disks (it can use any configuration to add them up, LVM, RAIDx, mount subpoints,...) and exports the filesystem to the network

Clients will be served by NAS2 as single share.

Either NAS can be NAS1 or NAS2, as long as they can export iSCSI volumes or import them.

This change of layout means you have to backup, recreate the filesystems and then restore.

Eduardo Trápani
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