The business owner is the person or entity that has the authority and responsibility for defining the purpose and scope of the processing of personal data, as well as the expected outcomes and benefits. The business owner is also accountable for ensuring that the processing of personal data complies with the applicable laws and regulations, such as the General Data Protection Regulation (GDPR) or the Data Protection Act 2018 (DPA 2018).
One of the requirements of the GDPR and the DPA 2018 is to adhere to the principle of storage limitation, which states that personal data should be kept for no longer than is necessary for the purposes for which it is processed1. This means that the business owner should determine and justify how long they need to retain personal data, based on factors such as:
The nature and sensitivity of the personal data
The legal or contractual obligations or rights that apply to the personal data The business or operational needs and expectations that depend on the personal data The risks and impacts that may arise from retaining or deleting the personal data The business owner should also establish and document the conditions and methods for the destruction of personal data, such as:
The criteria and triggers for deciding when to destroy personal data
The procedures and tools for securely erasing or anonymising personal data The roles and responsibilities for carrying out and overseeing the destruction of personal data The records and reports for verifying and evidencing the destruction of personal data Therefore, retention periods and conditions for the destruction of personal data should be determined by the business owner, as they are in charge of defining and managing the processing of personal data, as well as ensuring its compliance with the law.

The best way to sanitize a hard disk for reuse to ensure the organization's information cannot be accessed is data wiping. Data wiping is a process that overwrites the data on the hard disk with random or meaningless patterns, making it unrecoverable by any software or hardware methods. Data wiping can provide a high level of security and assurance that the organization's information is permanently erased from the hard disk, and that it cannot be accessed by unauthorized parties or malicious actors.
Re-partitioning is not a way to sanitize a hard disk for reuse, but rather a way to organize the hard disk into different logical sections or volumes. Re-partitioning does not erase the data on the hard disk, but only changes the structure and allocation of the disk space. Re-partitioning may make the data inaccessible to the operating system, but not to other tools or methods that can scan or recover the data from the disk sectors.
Degaussing is a way to sanitize a hard disk for reuse, but only for magnetic hard disks, not solid state drives (SSDs). Degaussing is a process that exposes the hard disk to a strong magnetic field, which disrupts and destroys the magnetic alignment of the data on the disk platters. Degaussing can effectively erase the data on magnetic hard disks, but it can also damage or render unusable the electronic components of the hard disk, such as the read/write heads or circuit boards. Degaussing also does not work on SSDs, which store data using flash memory cells, not magnetic media.
Formatting is not a way to sanitize a hard disk for reuse, but rather a way to prepare the hard disk for use by an operating system. Formatting is a process that creates a file system on the hard disk, which defines how the data is stored and accessed on the disk. Formatting does not erase the dataon the hard disk, but only deletes the file system metadata and marks the disk space as available for new data. Formatting may make the data invisible to the operating system, but not to other tools or methods that can restore or recover the data from the disk sectors.
References:
How to Wipe A Hard Drive for Reuse? Check the Quickest Way to Wipe A Hard Drive - EaseUS 1 HP PCs - Using Secure Erase or HP Disk Sanitizer 2 HOW to QUICKLY and PERMANENTLY SANITIZE ANY DRIVE (SSD, USB thumb drive ...)

After migrating infrastructure to the cloud, it's imperative to test the disaster recovery plan (DRP) to ensure its effectiveness in the new environment. Without evidence of DRP testing post-migration, the organization cannot be certain that it can recover and continue operations during a disaster. While updating the DRP and configuring redundancy are essential steps, their effectiveness can only be validated through rigorous testing.
Retaining previous infrastructure is less relevant if the cloud environment is properly configured and tested for disaster recovery.
References:
* ISACA CISA Review Manual, 28th Edition, Chapter 4: Information Systems Operations and Business Resilience.

When auditing the closing stages of a system development project, the most important consideration should be the user acceptance test (UAT) results. The UAT is a critical phase of the system development life cycle (SDLC) that ensures that the system meets the functional requirements and expectations of the end users. The UAT results provide evidence of the system's quality, performance, usability, and reliability. Control requirements, rollback procedures, and functional requirements documentation are also important considerations, but they are not as crucial as the UAT results in determining if the system is ready for deployment. References: CISA Review Manual (Digital Version)1, page 325.