---
name: "rdac"
section: "4"
platform: "openbsd"
package: "man"
version: "8.0-current-20261101"
release: "OpenBSD 8.0-current (2026-11-01)"
platforms: ["openbsd"]
url: "https://new.carta.tech/rdac"
---

# rdac(4)

Engenio/LSI RDAC SCSI devices

## NAME

**rdac** – Engenio/LSI RDAC SCSI devices

## SYNOPSIS

**rdac\* at scsibus?**

## DESCRIPTION

The **rdac** driver attaches to Engenio/LSI RDAC SCSI logical units. Each path to an active service processor attached to by **rdac** is presented to [mpath(4)](/mpath/4.md) which uses it as a backend to the logical unit attached to its own scsibus(4).

## SEE ALSO

[ioctl(2)](/ioctl/2.md), [intro(4)](/intro/4.md), [mpath(4)](/mpath/4.md), [scsi(4)](/scsi/4.md)

## HISTORY

The **rdac** driver first appeared in OpenBSD 5.0.

## AUTHORS

David Gwynne ⟨*dlg@openbsd.org*⟩.