RAID 1, or mirroring, is a storage configuration where data is duplicated across two or more drives in real time. Every file you save is written to both drives at once, so if one drive fails, your data remains intact on the other.
This differs from a simple backup. With RAID 1, the mirroring happens automatically at the drive level, not through software running on your computer. You see only one drive's worth of usable space (the capacity of the smaller drive if they differ), but you gain redundancy.
How it works in practice:
- You save a document to your RAID 1 array. It writes to Drive A and Drive B simultaneously.
- Drive A fails. You swap it out for a new drive.
- Your RAID controller rebuilds the new Drive A from Drive B's copy.
- You lose no data during this process.
RAID 1 suits small offices, creative professionals storing valuable project files, and anyone who cannot afford downtime. It does not increase speed significantly, though read performance may improve slightly. It costs more than a single drive (you need at least two identical or similar drives) and halves your usable capacity.
A RAID 1 setup requires either a dedicated RAID controller card in your computer, a NAS (network-attached storage) device, or external RAID enclosure. Some motherboards include basic RAID 1 support through software RAID, though hardware RAID is more reliable for critical data.
When choosing RAID 1 storage, verify that both drives are the same capacity and speed, and check the rebuild time estimate. Longer rebuild windows increase the risk of a second failure during recovery.