# Understanding write-cache mode for physical drives

When using the write-cache-mode option, you can choose from two available settings.

## Write back

For the write back setting, the controller sends data to the physical drive for storage. Subsequently, the physical drive sends a confirmation to the controller before actually storing the data. Doing so increases performance, but also contains an element of risk.

Attention:
  1. It is possible to lose data if a power outage occurs while using the write back setting. Consider carefully whether to enable write back on a physical drive. Depending on how you use the system, write back might be undesirable.
  2. If you set this feature to write back, wait at least 10 seconds after your last operation before you turn off your system. Failure to follow this practice might result in lost data.

## Write through

For the write-through setting, the controller sends data to the physical drive for storage. Subsequently, the physical drive stores the data; then, sends a confirmation to the controller. Using write through can decrease performance, but has no risk of losing data.

## More information

- Changing the write-cache mode on a physical drive (action)
- Fine-tuning your system

Glossary | Contents

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