[This is preliminary documentation and subject to change]

# Global Registry Entries

All other topics have an introduction to the properties keys. Please add an overview of the Global Registry Properties Keys. From what I understand, these affect a lot of things and should be described as affecting all IIS services. However, this is not implied from the other topics.

CacheSecurityDescriptor
Registry Path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet \Services\InetInfo\Parameters
Data Type: REG_DWORD
Default value: 1 (enabled)
Range: 0 - 1
Specifies whether security descriptors are cached for file objects. IfWhen CacheSecurityDescriptor is enabled (with the value of 1), IIS retrieves security permissions when caching a file object and willdoes not need to gain access to the file object to check access rights for new users. The feature is useful only if you have more than one user account (not usingWeb server does not use only anonymous authentication).

CheckCertRevocation
Registry Path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet \Services\InetInfo\Parameters
Data Type: REG_DWORD
Default value: 0 (disabled)
Range: 0 - 1
Specifies whether client certificates are checked for revocation by IIS.This C heckCertRevocation is disabled by default because checking for common certificate issuers is typically done over the Internet and has severe performance impact. However, enabling C heckCertRevocation may be useful if you issue your own certificates and the revocation process is local.

DisableMemoryCache
Registry Path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet \Services\InetInfo\Parameters
Data Type: REG_DWORD
Default value: 0 (disabled)
Range: 0 - 1
Disables server caching. This keyYou must configure DisableMemoryCache using the Registry Edit utility; you cannot use the IIS snap-in.

ListenBackLog
Registry Path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet \Services\InetInfo\Parameters
Data Type: REG_DWORD
Default value: 15
Range: 1 - 250
Specifies the maximum number of active connections to hold in the queue while they wait for server attention. Enhanced IIS functionality generally makes it unnecessary to use or modify this entry, although extremely heavy usetraffic might benefit by increasing this value up to 50.

MaxCachedFileSize
Registry Path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet \Services\InetInfo\Parameters
Data Type: REG_DWORD
Default value: 256KB (262,144 bytes)
Controls the maximum size of cache files. The default is 256KB if no value is present.

MaxConcurrency
Registry Path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet \Services\InetInfo\Parameters
Data Type: REG_DWORD
Default value: 0
Range: 0 - 4,294,967,295
Specifies the amount of concurrency that a system should provide. IIS uses c completion ports are used by IIS for to handle e input-output (I/O). In general,it is not good to you should not have more than one thread running and conflicting on shared memory or locks. This key specifies how many threads per processor should be allowed to run simultaneously if there is a pending I/O operation. The specific A value of 0 allows the system to make the intelligent choice of the number of threads to use. Any nonzero value specifies that the system should allow that many threads per processor to run simultaneously.

MaxPoolThreads
Registry Path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet \Services\InetInfo\Parameters
Data Type: REG_DWORD
Default value: 4
Range: 0 - 4,294,967,295
Specifies the number of pool threads to create per processor. Pool threads watches for the network for requests and processes itthe incoming requests. The MaxPoolThreads count does not include threads that are consumed by ISAPI applications. By default, only four CGI applets can run concurrently. If you run many more than four CGI applications, you should increase this value in order to increase the throughput. Optionally, you could set the UsePoolThreadForCGI value (under ..\Services\W3SVC\Parameters) to FALSE (0), but this is somewhat dangerous because it can significantly decrease performance during high usage of CGI applications. Generally, it is not good to you should not create more than 20 threads per processor.

MemCacheSize
Registry Path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet \Services\InetInfo\Parameters
Data Type: REG_DWORD
Default Value: approximately one half the available physical memory and calibrated in megabytes
Range: 0 - 2500MB
Controls the size of the cache. The D default value is dynamically adjusts ed every 60 seconds.

PoolThreadLimit
Registry Path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet \Services\InetInfo\Parameters
Data Type: REG_DWORD
Default value: 2 * # MB
Range: 0 - 4,294,967,295
Each pPool threads watches for the network for requests and processes itthe incoming requests .Specifies the maximum number of pool threads that can be created in the system. PoolThreadLimit is a hard limit that includes all IIS threads. PoolThreadLimit and willis always be greater than or equal to MaxPoolThreads.

MinFileKbSec
Registry Path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet \Services\InetInfo\Parameters
Data Type: REG_DWORD
Default value: 1000
Range: 1 - 8192
When a Web server sends a file to a client, a timeout is established for how long the server will allow the transfer to continue before ending it the connection. The timeout chosen is the maximum of the C connection T timeout specified in the IIS snap-in plus the size of the file, and divided by the value specified as for MinFileKbSec s. For example, a file size of 100 kilobytes is given a timeout of 100 seconds, or the C connection T timeout if the latter is greater. Note that the registry name is misleading, because the value is in bytes, not kilobytes as the name implies.

ObjectCacheTTL
Registry Path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet \Services\InetInfo\Parameters
Data Type: REG_DWORD
Default Value: 30 (seconds)
Range: 0 - 4,294,967,295
This registry entry controls the Time To Live (TTL) setting, which defines the length of time that objects are held in cached memory. If an object in the memory cache has not been referenced for the defined period, that object will be phased out of the cache. If system memory is limited, or the server's contents are dynamic, you can use a lower TTL to prevent system memory from being used to cache a large number of volatile objects. Setting ObjectCacheTTL to 0xFFFFFFFF disables the object-cache scavenger and allows cached objects to remain in the cache until they are overwritten. Disabling the cache scavenger is useful if your server has ample system memory and your data is relatively static.

ThreadTimeout
Registry Path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet \Services\InetInfo\Parameters
Data Type: REG_DWORD
Default value: 24 * 60 * 60 (24 hours)
Range: 0 - 4,294,967,295
Specifies the amount of time an input-output (I/O) processing thread should be maintained even if there is no I/O activity on the system. In general when there is no I/O activity and no requests outstanding, the server remains is idle and does not consume memory. But if that situation the server continues and exceeds the ThreadTimeout interval, then the I/O processing thread is stopped. Units are in seconds.

UserTokenTTL
Registry Path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet \Services\InetInfo\Parameters
Data Type: REG_DWORD
Default value: 15 * 60 (15 Minutes)
Range: 0 - 0x7FFFFFFF
When a request is made to the server, the security credentials for the request (or the configured anonymous user) are used to create a user token on the server. The server impersonates this user token when accessing files or other system resources (see CacheSecurityDescriptor). The token is cached so that the Windows logon takes place only the first time the user accesses the system or after the user's token has fallen out of the cache. Integrated Windows authentication tokens are not cached. Units are in seconds.

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