Shulou(Shulou.com)06/02 Report--

Recently, it has been found that the available memory of a machine in the business, windos2008, has continued to decrease, and today it has been reduced to 2G.

The memory sum of the running process is calculated, and it is found that it is not consistent with the reality (I don't know where the remaining 4G is).

Later, RAMMap v1.51 was used to analyze the memory. Download the address, please click here

Analysis and discovery

Mapped file takes up a lot of 4 gigabytes of memory, according to Microsoft's website:

You experience performance issues in applications and services in various versions of Windows XP, Windows Vista, Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2. Additionally, you notice the following symptoms:

1) Available memory is almost exhausted.

2) The system file cache consumes most of the physical RAM.

3) There is a continuous and high volume of cached read requests to the hard disk.

If there is a continuous and high volume of cached read requests from any process or from any driver, the working set size of the system file cache will grow to meet this demand. The system file cache consumes the physical RAM. Therefore, sufficient amounts of physical RAM are not available for other processes

In other words, there is no limit to the cache of the file system, and the cache of the file system continues to occupy physical memory.

Solution:

The official solution is to limit the memory (no continuous increase in occupied memory is allowed)

To install Windows Dynamic Cache Service, click here to download the address

Registration service

Dynamic Cache Registry settings, here I set 10g (12g physical memory)

[HKEY_LOCAL_MACHINE\ SYSTEM\ CurrentControlSet\ Services\ DynCache\ Parameters]

"MaxSystemCacheMBytes" = dword:00002800

"MinSystemCacheMBytes" = dword:00000064

"SampleIntervalSecs" = dword:0000003c

"CacheUpdateThresholdMBytes" = dword:00000064

Just set MaxSystemCacheMBytes, which is set to 10G here

Start the Dynamic Cache service in the service. Note: the application needs to be restarted.

Keyword description:

Process Private: memory allocated to a single Process

Mapped File: the memory space used to store the archive content cache (Cache)

Shared Memory: memory pages shared by multiple Process (Page, memory management unit)

Page Table: a paging table used to describe virtual memory addresses (PTE,Page Table Entries is a stroke by stroke)

Paged Pool: allows moving to the core cluster memory of the hard disk (Kernal Pool Memory)

Nonpaged Pool: not allowed to move to the core cluster memory of the hard disk

System PTEs: PTE related to system paging, such as Imax O space, core stack, memory description list, etc.

Session Private: log in to session-related memory

Metafile: is part of the system cache and contains NTFS Metadata (including MFT and other NTFS Metadata files). In MFT, each file attribute record occupies 1K, while a file has at least one attribute record, plus other NTFS Metadata files, when there are a large number of files, this piece will grow very quickly.

AWE: the associated memory space used to enable Address Windowing Extension technology (more commonly used in SQL or other DB)

Driver Locked: physical memory locked by the driver. It is mostly used for temporary small-volume applications of IPUBO. If RAMDisk is installed, it will also be counted in this area.

Kernel Stack: the core thread is stacked, and the more threads you have, the more you use.

Each category has the following fields:

Active: physical memory pages in use (Process Working Set or System Working Set) Standby: pages left in physical memory but not in use, reserved for quick reuse later Modified: similar to Standy, but the content has been modified, write back to the hard drive Modified no write before repeating use: similar to Modified But marked as no need to write back to the hard disk Transition: page Zeroed converted between categories: the content has been cleared for use, and the system increases significantly when the system is powered on, and it is gradually converted to StandbyFree over a period of time: pages that can be used but with residual previous data need to be converted to ZeroedBad before use: Mark damaged memory

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