REG: Server Service Entries, PART 2

• Windows NT operating system version 3.1
• Windows NT Advanced Server version 3.1

This is the second of two articles on these entries; for the other entries, see "Server Service Entries, Part 1".

SERVER SERVICE ENTRIES

With Registry Editor, you can modify the startup parameters for the Server service. Unless otherwise noted, these parameters are found in this path:

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet
   \Services\LanmanServer\Parameters

This is the second of two articles on these entries; for the other entries, see Server Service Entries, Part 1.

MinFreeConnections   REG_DWORD   2 to 5 items

Specifies the minimum number of free connection blocks maintained per endpoint.

MinFreeWorkItems   REG_DWORD   0 to 10 items

Specifies the minimum number of available receive work items that are needed for the server to begin processing a potentially blocking SMB. A larger value for this parameter ensures that work items are available more frequently for nonblocking requests, but it also increases the likelihood that blocking requests will be rejected.

MinKeepSearch   REG_DWORD   5 to 5000 seconds

Specifies the minimum amount of time that the server will keep incomplete MS DOS searches, even if more search entries are needed. This parameter only matters when the server is near the maximum number of open searches it is allowed.

MinLinkThroughput   REG_DWORD   0 to infinite bytes per second

Specifies the minimum link throughput allowed by the server before it disables raw and opportunistic locks for this connection.

MinRcvQueue   REG_DWORD   0 to 10 items

Specifies the minimum number of free receive work items needed by the server before it begins allocating more. A larger value for this parameter helps ensure that there will always be work items available, but a value that is too large is simply inefficient.

NetworkErrorThreshold   REG_DWORD   1 to 100 percent

Triggers an alert whenever the percentage of failing network operations relative to total network operations exceeds this value during the AlertSched interval.

NumBlockThreads   REG_DWORD   1 to 10 threads

Specifies the number of threads set aside by the server to service requests that can block the thread for a significant amount of time. Larger values can increase performance but use more memory. A value that is too large can impede performance by causing excessive task switching.

OpenSearch   REG_DWORD   1 to 2048 searches

Specifies the maximum number of outstanding searches on the server, per connection. A single client can have up to the OpenSearch number of active searches. This includes all types of searches, including MS- DOS, OS/2, and Windows NT.

OplockBreakWait   REG_DWORD   10 to 180 seconds

Specifies the time that the server waits for a client to respond to an oplock break request. Smaller values can allow detection of crashed clients more quickly but can potentially cause loss of cached data.

RawWorkItems   REG_DWORD   1 to 512 items

Specifies the number of special work items for raw I/O that the server uses. A larger value for this parameter can increase performance but costs more memory.

ScavTimeout   REG_DWORD   1 to 300 seconds

Specifies the time that the scavenger remains idle before waking up to service requests. A smaller value for this parameter improves the response of the server to various events but costs CPU cycles.

ScavQosInfoUpdateTime   REG_DWORD   0 to 100,000 seconds

Specifies the time that can pass before the scavenger goes through the list of active connections to update the link information.

SessConns   REG_DWORD   1 to 2048 connections

Specifies the maximum number of tree connections that can be made on the server via a single virtual circuit.

SessOpens   REG_DWORD   1 to 2048 files

Specifies the maximum number of files that can be open on a single virtual circuit.

SessUsers   REG_DWORD   1 to 64 users

Specifies the maximum number of users that can be logged on to a server via a single virtual circuit.

SizReqBuf   REG_DWORD   512 to 65536 bytes

Specifies the size of request buffers that the server uses. Small buffers use less memory; large buffers may improve performance.

ThreadCountAdd   REG_DWORD   0 to 10 threads

The server uses one worker thread per processor for the computer it is running on. This parameter indicates how many additional threads the server should use. More threads can improve performance but cost memory. Too many threads can hurt performance by causing excessive task switching.

ThreadPriority   REG_DWORD   0, 1, 2, or 15

Specifies the priority of all server threads in relation to the base priority of the process. Higher priority can give better server performance at the cost of local responsiveness. Lower priority balances server needs with the needs of other processes on the system. Values 0 to 2 are relative to normal or background processes. The default value of 1 is equivalent to the foreground process. A value of 15 runs the server threads at real-time priority-which is not recommended.

Users   REG_DWORD   1 to infinite

Specifies the maximum number of users that can be simultaneously logged on to the server.

XactMemSize   REG_DWORD   64 KB to 16 MB0

Specifies the maximum amount of virtual memory used by the Xactsrv service. A larger value for this parameter helps ensure that memory is available for downlevel clients but costs virtual address space and potentially costs pageable memory.

Reference: "The Windows NT Resource Kit for Operating System Version 3.1".