Be aware of the following:Ī reboot is required for changes to this regkey to take effect. If the default size of 5 GB does not work well for your configuration, it is recommended to try increasing the limit in 256-MB increments until performance is satisfactory. This threshold can be controlled with the following regkey: HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\RemoteFileDirtyPageThreshold. For some configurations and workloads, a different number will perform better. This remote dirty page threshold is 5 GB per file by default. This can result on occasional slowdowns during heavy write activity, but eliminates the risk of a timeout in most cases. A separate dirty page threshold for remote writes is implemented, and an inline flush will be performed when it is exceeded. In Window Server 2016 and forward, a mitigation is put in place to reduce the likelihood of timeouts. This can cause a flush of a large amount of data to the disk, which can lead to long delays if the storage is slow, resulting in timeouts for the remote connection.
#Cache memory cleaner windows 10 windows
Prior to Windows Server 2016, in such a scenario, if the dirty page threshold in the cache is reached, further writes will behave as if there were write-through. This issue may occur when a large amount of data is written from a fast remote client to a slow server destination. This problem is indicated if a system experiences occasional slowdowns during writes from a remote client. Remote file dirty page threshold is consistently exceeded It is highly recommended that FILE_FLAG_RANDOM_ACCESS not be used by applications. Pages that are accessed at low memory priority are removed from the working set more aggressively.Ĭache Manager, starting in Windows Server 2016 further mitigates this by ignoring FILE_FLAG_RANDOM_ACCESS when making trimming decisions, so it is treated just like any other file opened without the FILE_FLAG_RANDOM_ACCESS flag (Cache Manager still honors this flag to disable prefetching of file data). You can still cause system cache bloat if you have large number of files opened with this flag and accessed in truly random fashion. This can be achieved using the SetThreadInformation API. An alternative solution for the app vendor might be to use low memory priority when accessing the files. This situation has been mitigated to some extent by working set trimming improvements in Windows Server 2012+, but the issue itself needs to be primarily addressed by the application vendor by not using FILE_FLAG_RANDOM_ACCESS. At the same time, this flag instructs Cache Manager to disable prefetching of file data. FILE_FLAG_RANDOM_ACCESS flag is a hint for Cache Manager to keep mapped views of the file in memory as long as possible (until Memory Manager doesn't signal low memory condition). This issue is described in detail in KB article 2549369. This usually indicates that some application on the server is opening numerous large files using CreateFile API with FILE_FLAG_RANDOM_ACCESS flag set. This problem is indicated by a high number of active Mapped file pages in RAMMAP output. System file cache contains memory mapped files In Windows Server 2012+, the architecture has been redesigned and this problem should no longer exist. The problem used to be mitigated by DynCache tool. This problem might have been observed on busy servers with millions of files being accessed, thereby resulting in caching NTFS metafile data not being released from the cache. This problem is indicated by a high number of active Metafile pages in RAMMAP output, as shown in the following figure. System file cache contains NTFS metafile data structures If Memory\Available Mbytes is low and at the same time Memory\System Cache Resident Bytes is consuming significant part of the physical memory, you can use RAMMAP to find out what the cache is being used for. Memory\Available (in Bytes, KBytes, or MBytes) Memory\Long-Term Average Standby Cache Lifetime (s) < 1800 seconds
When this situation results in the system being sluggish, you can determine whether the server is facing one of these issues.
Before Windows Server 2012, two primary potential issues caused system file cache to grow until available memory was almost depleted under certain workloads.
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