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.TH DPSERVER 4 "August 2024" "Xsan File System"
.SH NAME
dpserver \- Xsan File System Proxy Client Configuration
.SH SYNOPSIS
.na
.nh
.HP
.B /Library/Preferences/Xsan/dpserver
.HP
.BI /Library/Preferences/Xsan/dpserver. VolName
.ad
.hy
.SH DESCRIPTION
The Xsan File System
\fBdpserver\fR file 
is a configuration file used to control
the
Stornext Distributed LAN Server (also called Proxy Server or Gateway)
on Linux systems.
This file is required in order to start a Proxy Server and is
consulted when a \fBmount\fP command specifies the Proxy 
Server option.
.PP
The \fBsndpscfg\fP command is normally used to generate and maintain
\fBdpserver\fP files on non-Windows systems - see
.BR sndpscfg (8)
for details.  To view and adjust the Proxy Server settings on Windows
systems, use the LAN Client/Gateway tab in the Client Configuration tool
instead.
.SH SYNTAX
At minimum, the \fBdpserver\fP file specifies the network interfaces to use
for Proxy Server.
It can also be used to override various Proxy Server tuning parameters.
.PP
There can be both file-system-specific
.BI dpserver. VolName
files
and a default \fBdpserver\fP file.  If a file-system-specific
.BI dpserver. VolName
file exists, it will be used in preference to the
default \fBdpserver\fP file.
.PP
The format rules for a line in the \fBdpserver\fR file are:

Any line beginning with "#" is considered a comment line.

Blank/empty lines are ignored.
.PP
There are several keywords:
.Cs
    interface \fIifname\fP [address \fIipaddr\fP]
    transfer_buffer_size_kb \fIn\fP
    transfer_buffer_count \fIn\fP
    server_buffer_count \fIn\fP
    tcp_window_size_kb \fIn\fP
    daemon_threads \fIn\fP
    server_conn_count \fIn\fP
.Ce
.PP
The keywords are interpreted as follows:
.PP
The \fBinterface\fP keyword specifies the name of a network interface (e.g.,
\fBeth0\fP) to use for Proxy Client traffic.
If a NIC has been assigned only one IP or IPv6 address, then only the interface
name needs to be specified. If the NIC has been assigned more than one address
(multiple IP addresses, multiple IPv6 addresses, or both IP and IPv6 addresses),
then the \fBaddress\fP keyword and one IP or IPv6 address should also be
specified.  If a single \fBinterface\fP entry exists for the NIC and the address
is omitted, the "main" address assigned to the interface is used and other
assigned addresses are ignored.  Finally, if an \fBinterface\fP entry exists with the
address omitted and another interface entry exists for the same NIC
containing an address, the specified address is used.
.PP
At least one \fBinterface\fP keyword must be specified in the file in order for a Disk
Proxy Client Server to be started.
.PP
The remaining keywords are used to override the default values for tunable
parameters.
Note that these values are propagated from the Proxy  
Servers to the Proxy Clients
, and thus can affect the behavior of both.
Note also that not all tuning parameters affect all platforms.
.PP
The optional \fBtransfer_buffer_size_kb\fP keyword specifies the size in
Kilobytes of the socket transfer buffers used for Proxy Client I/O.
The default value is 256 and values between 32 and 4096 are allowed,
however, the value will be rounded down to the nearest power of two.
(e.g. a value of 4000 is rounded down to 2048.)
.PP
The optional \fBtransfer_buffer_count\fP keyword specifies the number of
socket transfer buffers used per connection for Proxy Client I/O.
Note that this parameter is not used on Linux Proxy 
Servers or Clients.
However, it is used by Windows Proxy Clients, and the value is passed
to them by Linux Proxy Servers.
The default value is 16 and values between 4 and 128 are allowed.
.PP
The optional \fBserver_buffer_count\fP keyword specifies the number of
I/O buffers that will be allocated per network interface on the
Proxy Server.
The default value is 24 and values between 4 and 512 are allowed.
.PP
The optional \fBtcp_window_size\fP keyword specifies the size in Kilobytes of
the TCP window used for Proxy Client I/O connections.
The default value is 0 and values between 0 and 16384 are allowed.
The setting of 0 has a special meaning, which is that no change
is made to the default system value. This allows Linux autotuning
to adjust the receive buffer size and TCP window size
dynamically for each connection. Quantum recommends this setting when
autotuning is enabled, which is the default for recent Linux versions.
.PP
The optional \fBdaemon_threads\fP keyword specifies the number of kernel
threads on the server that will be used to service Proxy Client I/O requests.
The default value is 8 and values between 2 and 256 are allowed.
.PP
The optional \fBserver_conn_count\fP keyword controls how many connections
a client makes to each gateway. This allows the use of multiple TCP links
over a single physical subnet rather than having to use multiple subnets
and physical NICs.
The default is 1 and up to 16 connections may be configured.
This parameter requires updated logic on the MDC,
gateways and DLC clients. If any of these is backrev code, the client
will only use one connection per network.
.SH HA ENVIRONMENTS
If you choose to configure the Distributed LAN Server on a StorNext
cluster running in High Availability (HA) mode, each HA node must have
its own dpserver files detailing the NICs on that node.  The
\fBdpserver\fR files are not synchronized between HA pairs.
.PP
If the Distributed LAN Server is configured after converting to HA,
the file system(s) running as Distributed LAN servers must be
unmounted and mounted again to service DLC requests.
.PP
In StorNext startup and failover
situations, the VIP is dynamically associated with a physical address
on the Primary server.  Do not use VIP interfaces when setting up the
dpserver configuration file, or it will not be available when the node
is running as Secondary.  The physical interface and IP address should
be used in this situation.
.SH EXAMPLE CONFIGURATION FILE
A very basic dpserver configuration file
.Cs
interface eth0
.Ce
.PP
A basic multi-interface dpserver configuration file
.Cs
interface eth0
interface eth1
interface eth2
interface eth3
.Ce
.PP
A more complex dpserver configuration file
.Cs
interface eth1 address 10.3.21.2
tcp_window_size_kb 64
transfer_buffer_size_kb 256
transfer_buffer_count 16
server_buffer_count 8
daemon_threads 8
.Ce
.PP
.SH LIMITATIONS
Only the \fBLinux\fP platform is supported with dpserver and sndpscfg commands
.PP
To view and adjust the Proxy Server settings on Windows systems, user the LAN Client/Gateway table in the Client Configuration tool instead.
.SH FILES
.I /Library/Preferences/Xsan/dpserver
.br
.IR /Library/Preferences/Xsan/dpserver. VolName
.SH "SEE ALSO"
.BR mount_acfs (8),
.BR sndpscfg (8)