
WSD Farm Parameters
The WSD (+
Pro, DS, NP) Farm Table window displays the following:
- IP Address A
virtual IP address representing the farm to the clients.
- Farm Name Enter
a name, up to 50 characters in length, to describe the WSD farm.
- Admin. Status
Can be one of the following options:
-
Enable The
farm is active. All users are balanced between the servers.
-
Disable The
farm is inactive. Clients connecting to the farm will not be served.
- Dispatch Method
The method used to determine to which server in the farm traffic will be
directed:
-
Cyclic
Directs traffic to each sever one by one (round robin).
-
Least Traffic
Directs traffic to the server with the least traffic.
-
Least Users Number
Directs traffic to the server with the least amount of
users.
-
Local Least Traffic
Directs users to the server with the least traffic, from this
farm only (i.e., traffic from other farms will not be considered).
-
Local Least Users
Number Directs users to the server with the fewest users,
from this farm only (i.e., users of other farms will not be considered).
-
nt-1 The
WSD will start querying the farm's servers for Windows NT SNMP
statistics. The WSD redirects the farm's clients to the least busy
server according to the servers' reported statistics. This method may be
used only with Windows NT servers. The parameters are considered
according to the weights configured in the first Windows NT weights
scheme (see the Windows NT Weights Table).
-
nt-2
Similar to nt-1, but using the second weights scheme.
-
private-1
When choosing this method, the WSD will query the farm's servers for
private SNMP parameters, as defined in the first private weights scheme
(see the Private Weights Table). The ratios of users on the servers will
be balanced according to the reported statistics.
-
private-2
Similar to private-1, but using the second weights scheme.
- Multiplexed Farm Port
Enables applications on the servers to be available on different
ports. Multiplexed ports can be defined in each farm. The value can be FTP,
HTTP, SMTP, DNS, NNTP, HTTPS, Disable, or any port number you enter
manually.
- Distributed Threshold
Determines the threshold of the number of users served by the local
(regular) servers; above this threshold, the WSD DS/NP starts redirecting
clients to the remote servers and to other WSD DS / NP devices in
distributed locations.
- Capacity Threshold
Determines the threshold on the number of users served by the local
servers, above which the WSD DS/NP will not receive clients from other WSD
DS/NP devices, and will serve only local clients.
- Redirection Mode
Defines the redirection method:
- HTTP Redirection
The WSD DS / NP uses HTTP redirection for sending HTTP sessions
to remote sites. Other sessions (not HTTP) will be handled by the local
servers only.
- Triangle
Redirection All clients (including HTTP) are redirected by
the triangulation method.
- HTTP & Triangle
Redirection HTTP sessions are redirected by the HTTP
redirection. All other sessions are redirected by the triangulation
method.
- DNS Redirection
The WSD DS / NP can operate as a DNS redirector as well as a
session redirector. If the WSD is defined as the farm's authoritative
DNS, and DNS redirection is enabled, then the dispatching decision takes
place in the DNS resolution stage and the reply is for the distributed
site address. This mode is more efficient, because only one request
comes to the WSD. On the other hand, when using proximity, it is
possible that the requesting host (the server that will also receive the
redirection) is not the client, but just one of the DNS servers on the
network: thus the redirection will always be to the closest server on
the network, but not always to the server closest to the client.
- DNS & HTTP & Triangle
Redirection DNS redirections is used for DNS queries. If the farm IP is used, HTTP
sessions are redirected by the HTTP redirection. All other sessions are redirected by the
triangulation method.
- No Redirection
The WSD DS / NP does not redirect clients of this farm to
any of remote or distributed servers. This also disables the dynamic
proximity mechanism for the farm.
- Redundancy Mode
For redundancy operation:
- Regular The
farm is operating regularly on this WSD device.
- Backup The
farm is not operational, and it backups another farm on another WSD
device. When the other farm fails, this farm takes over and becomes
operational.
- Sessions Mode
The method used to handle new sessions:
- Regular
Each client that connects to the farm represents one entry in the Client
Table.
- EntryPerSession
Each session a client opens is recorded in the client table and
is balanced separately. This provides more accurate minimum-user load
balancing. When disabled, all of the client's sessions are considered a
single session, providing better performance.
- ServerPerSession
Different sessions opened by a client's application will be
served by different servers, according to the load balancing algorithms.
This option enhances load-balancing performance but may hinder some
applications that depend on being served by the same server. It also may
overload the WSD's internal tables. This option overrides the New Entry
On Source Port option.
- Remove on Session End When the
client session ends, the client's entry is immediately removed from the
Client Table. This option is automatically enabled when New Entry on
Source Port is enabled.
To configure
a new farm:
- From the WSD menu, choose Farm Parameters.
The Farm Table window opens.
- Click
.
The Farm Table Insert window opens
containing the fields listed above as well as the following:
- Client Aging Time
The amount of time a non-active client is kept in the client
table (in seconds). As long as a client is kept in the client table, the
client will be connected to the same server.
- Connectivity Method
Indicates the method of checking for server availability. The
value can be Ping, FTP, HTTP, SMTP, DNS, NNTP, HTTPS, or any port number
you enter manually.
If Ping is selected, the
WSD pings the servers to verify valid communication. If "HTTP
Pages" is selected, the WSD will try to retrieve the web pages (as
configured in the "Home Page" field) from the servers. (You can configure which returned HTTP code indicates proper connection. Also, if the return of an HTTP code is not enough, you can have the device additionally check for the presence or absent of a text string, which is also configurable.) Any other value causes the WSD to attempt to connect to the specified
application port. If a Ping operation fails, or an application could not
be opened, this means that the server is down.
- Connectivity Check
Port The specific port to which to conduct the connectivity
check. There are a number of pre-set commonly used ports. For example,
"HTTP" automatically checks port 80. You can enter any port
number.
- Connectivity
Interval How often the Web Server Director polls the servers
(in seconds).
- Connectivity
Retries The number of polling attempts that should be made
before a server is considered inactive. This also applies to the reports
from other WSD DS/NP devices.
- Retrieval Frequency
To save unnecessary web page requests, web page retrieval can be
performed only periodically. Only once in a number of requests,
according to the retrieval frequency, the web page is requested.
Otherwise, a simple TCP check for port 80 will occur.
- Home Page
When choosing the "HTTP pages" check method, this field
defines the default web page which will be retrieved from the servers.
If this web page is unavailable, the server is considered down.
- DNS Redirection Fallback This feature is available only when using "DNS Redirection" as the selected Redirection Mode (see above). If the WSD has no local servers for the farm, the redirection mode specified here is used redirect the client.
- Click
.
The Farm Table Insert window closes.
- In the Farm Table window, click
. The farm is added to the list.
To view the servers of a specific farm:
- From the WSD menu, choose Farm Parameters.
The Farm Table window opens.
- Click Servers.
The Server
Table for Farm... Table opens.
To add a server
to a specific farm:
- From the WSD menu, choose Farm Parameters.
The Farm Table window opens.
- Click Servers.
The Server
Table for Farm... Table opens.
- Click
.
The Application Server Table Insert window
opens.
- Enter the appropriate information.
- Click
.
The Application Server Table Insert window
closes.
- In the Server Table for Farm... window, click
.
The
server is added to the list.
To view the
clients of a specific farm:
- From the WSD menu, choose Farm Parameters.
The Farm Table window opens.
- Click Client.
The Client
Table for Farm... Table opens.
To add a static
client to a specific farm:
- From the WSD menu, choose Farm Parameters.
The Farm Table window opens.
- Click Client.
The Client
Table for Farm... Table opens.
- Click
.
The Client Table Insert window opens.
- Enter the appropriate information.
- Click
.
The Client Table Insert window closes.
- In the Client Table for Farm... window, click
.
The
client is added to the list.