LUN-Löschung (Storage)

What is a LUN?

In large storage systems, such as a SAN (Storage Area Network), the system distributes data across many hard drives or SSDs. From these, it forms logical units for the servers. Each of these units receives a number, the LUN. A server sees a LUN like a normal hard drive, although the data physically resides on many drives, often in a RAIDarray.

Why a LUN has to be erased separately

If a LUN is merely removed in the storage system, only the assignment disappears. The data remains on the physical drives until it is overwritten. When a company frees up storage space, for example when a tenant changes, at the end of a lease or when switching to new systems, the LUN must therefore be overwritten beforehand. Special software erases the entire logical area for this and creates a report.

Situation	Usual approach
Storage system stays in operation	Overwrite the LUN with software, report per LUN
Storage system is decommissioned	Erase or destroy all physical drives individually

For a complete teardown, a LUN erasure alone is not enough, because spare drives and system areas can be left out. In that case, the individual drives are recorded and erased. Second IT erases removed drives with Blancco and destroys data carriers that cannot be erased in its own facility according to DIN 66399. More on teardown in the guide sell used servers.

Frequently asked questions about LUN erasure

What does LUN mean?

LUN stands for Logical Unit Number. The term originally comes from SCSI technology. Today it usually refers to a logical storage area that a storage system provides to a server.

Is it enough to delete a LUN in the storage system?

No. Removal only dissolves the assignment. The data remains on the physical drives. For secure erasure, the area must be overwritten beforehand.

What happens to the hard drives of a decommissioned SAN?

They are recorded individually, erased with certification or, if that is not possible, destroyed – in each case with proof per serial number.

When does a LUN have to be erased?

When storage is returned to a provider, reassigned, or when data has to be removed from a running system. Typical cases are a tenant change, the end of a lease or the switch to new systems.

How is a LUN erased securely?

Special software overwrites the entire logical area and creates a report. Neither does the system have to be shut down nor a hard drive removed. For a complete teardown, the individual drives are recorded and erased instead.