OS SSD failed after 3 years / 230TB - why is OS writing so much to the disk?

Microsoft Windows Client Documentation

A page file (also known as a "paging file") is an optional, hidden system file on a hard disk.

Functionality

Page files have the following functionalities.

-Physical extension of RAM

-Support for system crash dumps

Page files in Windows with large physical memory

When large physical memory is installed, a page file might not be required to support the system commit charge during peak usage.

The available physical memory alone might be large enough.

However, the reason to configure the page file size hasn't changed. It has always been about supporting a system crash dump, if it's necessary, or extending the system commit limit, if it's necessary. For example, when a lot of physical memory is installed, a page file might not be required to back the system commit charge during peak usage. The available physical memory alone might be large enough to do this.

Windows Internals 7 Chapter 5. Memory Management

Using data structures that the memory manager creates and maintains called page tables, the CPU

translates virtual addresses into physical addresses.

The actual translation process and the layout of the page tables and page directories (described

shortly), are determined by the CPU. The operating system must follow suit and build the structures correctly in memory for the whole concept to work.

Commit charge and commit limit.

There is a system-wide limit, called the system commit limit or simply the commit limit, on the amount of committed memory that can exist at any one time.

This limit corresponds to the current total size of all paging files plus the amount of RAM that is usable by the operating system.

Whenever virtual address space is created—for example, by a VirtualAlloc (for committed memory) or MapViewOfFile call—the system must ensure that there is room to store it, either in RAM or in backing store (on disk), before successfully completing the create request.

The purpose of the system commit limit and commit charge is to track all uses of these resources to ensure they are never overcommitted—that is, that there is never more virtual address space defined than there is space to store its contents, either in RAM or in backing store (on disk).

Conceptually, the system commit limit represents the total committed virtual address space that can be created in addition to virtual allocations that are associated with their own backing store (on disk) —that is, in addition to sections mapped to files.

Its numeric value is simply the amount of RAM available to Windows plus the current sizes of any page files.

If a page file is expanded or new page files are created, the commit limit increases accordingly.

If no page files exist, the system commit limit is simply the total amount of RAM available to Windows.

Starting with Windows 8.1 , MS tweaked the system default pagefile size to make it more relevant.

I'll post some screenshots later.

MurrayM

K8Toledo