I have some questions about BIG/SPAN. In my question I will talk about two hard drives spanned together.

  • How is the data spanned across the two drives? Will it span according to files or on byte level? Or does this depend on the controller?
  • Can you access the data of the hard drive which didn't failed without the origin controller? Is it possible to access the data of only one hard drive?

1 Answer 1


BIG/SPAN suffers all the same drawbacks as JBOD, except it presents as a partition (volume) rather then a drive.

So- It works”on a byte” level” would be closer then file - actually it works on a block level.

It does not let you access remaining data if the first drive fails You MIGHT have limited luck if other drives fail - for recovery purposes depending on the filesystem, fragmentation etc.

You cant rely on it working in the absence of the controller, but, I imagine it will work with a similar controller if you get lucky.

SPAN/BIG plays as fast and loose with your data as JBOD.

  • Depends on implementation. ZFS and btrfs can span multiple devices and store files redundantly, too, like 2× 500 GB drives and 1× 1 TB drive with everything doubled
    – endolith
    Jan 19, 2021 at 16:07

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