lockmgr

VOB database access arbitrator

APPLICABILITY

ClearCase (administrative command)

SYNOPSIS

Invoked at ClearCase startup time

DESCRIPTION

Each VOB host runs one database lock manager process, lockmgr. This process arbitrates transaction requests to all VOB databases on that host from ClearCase client programs throughout the network. The calling program polls lockmgr, which either grants or prohibits access to the requested data. If the data is available, the transaction proceeds immediately: the data is read or written, and output is returned to the calling program. If the data is unavailable (locked because another caller has been granted write access to the data), the caller waits until lockmgr grants it access to the data.

At system startup time, the Service Control Manager starts the lockmgr service with the options and default values described in the OPTIONS AND ARGUMENTS section. To change these values, create the following Windows registry key:

HKEY_LOCAL_MACHINE\SOFTWARE\Atria\ClearCase\CurrentVersion
LockMgrCmdLine: REG_SZ : -a almd -u num -f num

OPTIONS AND ARGUMENTS

SPECIFYING THE LOCKMGR SOCKET. Default: almd

-a almd

Specifies the name of the socket created by the lockmgr. Do not change this value.

SPECIFYING THE SIZE OF THE REQUEST QUEUE. Default: 128.

-q num

Specifies the number of lock requests for locks to be queued. The Lock Manager delays queuing lock requests in excess of this value. As a rule, this value ought to be five times the average number of users waiting for locks. (In this context, users means db_server processes and RPC server processes.)

SPECIFYING THE NUMBER OF USERS. Default: 128.

-u num

Specifies the number of concurrent users the Lock Manager supports. In this context, user means a db_server or vobrpc_server process. Each active view requires one vobrpc_server process for each VOB that the view accesses. Various operations that display VOB information (for example, from cleartool or Windows Explorer) will cause a db_server process to be allocated. In general, if the number of db_server and vobrpc_server processes on a single VOB server host approaches the number of users the Lock Manager is configured to support, increase the -u parameter.

SPECIFYING THE NUMBER OF FILES. Default:128.

-f num

Specifies the number of concurrent files the Lock Manager supports. In this context, file means one of the seven files that constitute a VOB database. If you have more than 36 VOBs on a single VOB server host, increase the -f parameter to a value at least seven times the number of VOBs on the host.

ERROR LOG

The lockmgr sends warning and error messages to the Windows Event Viewer.

SEE ALSO

albd_server, db_server, vobrpc_server