Cyclades AlterPath ACS, Справочник по командам

Страница: 45 / 420

AlterPath ACS Command Reference Guide
29
Device Access
2.2 Data Buffering
Data buffering can be done in local files or in remote files through NFS. When using
remote files, the limitation is imposed by the remote Server (disk/partition space) and
the data is kept in linear (sequential) files in the remote Server. When using local files,
the limitation is imposed by the size of the available ramdisk. You may wish to have data
buffering done in file, syslog or both. For syslog,
all.syslog_buffering and
conf.DB_facility are the parameters to be dealt with, and syslog-ng.conf file should be
set accordingly. (Please see Syslog-ng for the syslog-ng configuration file.) For the file,
all.data_buffering is the parameter to be dealt with.
Conf.nfs_data_buffering is a remote network file system where data buffering will be
written, instead of using the default directory /var/run/DB . When commented, it
indicates local data buffering. The directory tree to which the file will be written must
be NFS-mounted and the local path name is
/mnt/DB_nfs . The remote host must have
NFS installed and the administrator must create, export, and allow reading/writing to
this directory. The size of this file is not limited by the value of the parameter
s1.data_buffering, though the value cannot be zero since a zero value turns off data
buffering.
The conf.nfs_data_buffering parameter format is:
<server name or IP address>:<remote pathname>
If data buffering is turned on for port 1, for example, the data will be stored in the file
ttyS1.data in local directory /var/run/DB or in remote path name and server indicated by
conf.nfs_data_buffering .
Ramdisks
Data buffering files are created in the directory /var/run/DB . If the parameter
s<nn>.alias is configured for the port <nn>, this name will be used. For example, if the
alias is called bunny, the data buffering file will be named bunny.data.
Linear vs. Circular Buffering
For local data buffering, this parameter allows users to buffer data in either a circular or
linear fashion. Circular format (cir) is a revolving buffer file that is overwritten
whenever the limit of the buffer size (set by
all.data_buffering ) is reached. In linear
format (lin), data transmission between the remote device and the serial port ceases once
the 4k bytes Rx buffer in the kernel is reached. Then if a session is established to the
serial port, the data in the buffer is shown (
all.dont_show_DBmenu or
sxx.dont_show_DBmenu must be 2), cleared, and data transmission is resumed. Linear
buffering is impossible if flow control is set to none . Default is cir.