{{refimprove|date=November 2012}}A '''shared disk architecture''' (SD) is a distributed computing architecture in which the nodes share same disk devices but each node has its own private memory.<ref>{{Cite web|date=2020-05-18|title=Difference between Shared Nothing Architecture and Shared Disk Architecture|url=https://www.geeksforgeeks.org/difference-between-shared-nothing-architecture-and-shared-disk-architecture/|access-date=2021-02-24|website=GeeksforGeeks|language=en-US}}</ref>. The disks have active nodes which all share memory in case of any failures.<ref>{{Cite journal|title=Solar: Towards a Shared-Everything Database on Distributed
LogA '''shared-Structureddisk Storagearchitecture''' (SD) is a [[distributed computing]] [[Software architecture|architecture]] in which the nodes share same disk devices but each node has its own private memory.<ref>{{Cite web|date=2020-05-18|title=Difference between Shared Nothing Architecture and Shared Disk Architecture|url=https://www.csgeeksforgeeks.utah.eduorg/~dongxdifference-between-shared-nothing-architecture-and-shared-disk-architecture/paper/solar|access-atc.pdfdate=2021-02-24|website=GeeksforGeeks|language=en-US}}</ref> The disks have active nodes which all share memory in case of any failures.<ref>{{Cite journal|title=Solar: Towards a Shared-Everything Database on Distributed Log-Structured Storage|url=https://www.cs.utah.edu/~dongx/paper/solar-atc.pdf|journal=|pages=13|via=Solar}}</ref> In this architecture, the disks are accessible from all the cluster nodes. This architecture has quick adaptability to the changing workloads.<ref>{{Cite web|last=Rylan|first=John|date=1 April 2018|title=Big Database (Part 2): Database Architecture|url=https://dzone.com/articles/big-database-2-database-architecture|url-status=live|website=DZone}}</ref> It uses robust optimization techniques. It contrasts with [[shared nothing architecture]], in which all nodes have sole access to distinct disks.<ref name="stopford">{{cite web|date=November 24, 2009|title=Shared Nothing v.s. Shared Disk Architectures: An Independent View|url=http://www.benstopford.com/2009/11/24/understanding-the-shared-nothing-architecture/|accessdate=November 1, 2012}}</ref> Multiple processors can access all disks directly via intercommunication network and every processor has local memory.
It contrasts with [[shared-nothing architecture]], in which all nodes have sole access to distinct disks,<ref name="stopford">{{cite web |date=November 24, 2009 |title=Shared Nothing v.s. Shared Disk Architectures: An Independent View |url=http://www.benstopford.com/2009/11/24/understanding-the-shared-nothing-architecture/ |access-date=November 1, 2012}}</ref> and with [[Shared-memory architecture|shared-memory]], in which they also share memory.
Shared Disk has two advantages over Shared memory. Firstly, each processor has its own memory, the memory bus is not a bottleneck; secondly, the system offers a simple way to provide a degree of fault tolerance.▼
▲Shared Disk-disk has two advantages over Shared-memory. Firstly, each processor has its own memory, the memory bus is not a bottleneck; secondly, the system offers a simple way to provide a degree of fault tolerance.
[[File:Shared Disk Architecture.jpg|thumb|Shared Disk Architecture]]
