JBOD

Just a Bunch of Disks. Drives concatenated without redundancy. Each drive lives independently — no striping, no parity.

Min. drives
1
Usable capacity
sum(all drives)
Fault tolerance
0
Performance
Single-disk per file

How it works

Drives appear as one logical volume but data is NOT striped. The first file fills drive 1, then spills to drive 2, etc. When a drive fails, only the files that lived on that drive are lost; everything on the surviving drives remains accessible.

Formula: sum(drives)

JBOD — D = dataDrive 1D1D4D7D10Drive 2D2D5D8D11Drive 3D3D6D9D12
Layout diagram

Pros / Cons

Pros

  • Maximum usable capacity
  • Mixed drive sizes natural
  • One drive failure only loses that drive's files
  • No RAID controller complexity
  • Drives readable independently in any system

Cons

  • No redundancy on any single drive
  • No performance benefit — single-disk speeds
  • Manual management of which file lives where
  • One drive failure = some data lost (the data on that drive)

When to use

When data is already safe elsewhere (off-site backup, cloud sync). Bulk scratch storage. Append-only archives that are backed up.

When NOT to use

Anything you would mind losing without a backup. Use Unraid 1P or a RAID with parity instead.

Try it now

Related

RAID 0 →Block-level striping with no redundancy. Maximum capacity and speed; any drive failure wip... Unraid (1 parity) →Drive-independent parity. Each drive has its own filesystem; on failure only that drive's ... RAID 1 →Mirror across drives. Survives N−1 failures. Simplest path to reliable storage in a 2-bay ... Browse all RAID levels →RAID Levels
Bottom line: JBOD is concatenation without redundancy — capacity-efficient but unforgiving. Pair with backups or pick a parity RAID.