Adding Multitenant Storage Capability to the illumos Kernel

The open-source illumos kernel, descended from SunOS, includes highly-threaded, high-performance NFS, SMB (aka CIFS), and iSCSI target services. These classic storage services were invented in an era where multiuser systems were the primary method for sharing server resources. With the age of virtualization upon us, multitenant systems are the new battleground for shared server resources. While multithreaded implementations of the classic storage services have been around for decades, the implementations have had a single-namespace restriction that has limited their use in new, multitenant environments. The current methods of server virtualization do not respond well to the interrupt-driven storage environments, resulting in both reduced performance and overly complicated systems management for storage services.

In this session, the challenges facing kernel development in a multitenant world are examined and overcome. The old assumptions about name services and how they impact the security, isolation, and resource management requirements of storage services are no longer valid. The solution includes a deep dive into how the kernel reacts to requests that are inherently latency-sensitive and come in sudden, unpredictable bursts. Several alternative methods of providing multitenant storage services are compared and contrasted including Samba, BSD jails, and hypervisors.

The result is a flexible system designed to offer classic storage services to thousands of clients, each with different name services, easily managed using modern systems administration techniques.