Nimsoft® Monitor™
spooler Guide
v5.3 series
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Contents
Contents 5
Chapter 1: spooler
This description applies to spooler probe version 5.3x.
The Robot spooler receives messages from the probes and delivers them to the Hub.
The Robot acts as the connection point to the message bus and ensures that message
generated by a Probe reaches the 'Hub' to which the Robot is hooked up. When a Probe
posts a message, the message is always sent to a Spooler first. When the Spooler accepts
the message, it is guaranteed that the message will be delivered to the Hub even if the
Hub or the network for some reason is down. As soon as the Spooler delivers the
message to the Hub, its job is done. It is now up to the Hub to decide where to send the
message. It may be queued for delivery to other hubs within the Domain, or to service
processes subscribing to the 'subject' the message was posted under, or it may simply
be discarded. The Spooler is capable of holding the message until certain criteria are
met. When operating in 'spooling' mode, the flushing mechanism may be configured by
the system administrator to empty the queue based on various flushing criteria. The
spooler responds to commands over the registered port TCP/48001.
Spooling
A message is written to a spooling database before the probe gets a receipt on the
posting. The receipt contains a message identifier that follows the message to the
receiver. The spooling database is flushed every few seconds unless some flushing rules
are set by the administrator.
Flushing
Flushing of the spooling database can be controlled by a set of variables. This
functionality is useful for LAN's or standalone machines that are connected to a WAN
using dialup lines or ISDN.
■
turn flushing on and off
■
flush after a given number of messages is spooled
■
flush after a message with a given priority is spooled
■
flush on a given interval or time
Storm protection
Storm protection can be enabled to protect message receivers from large quantities of
simultaneous messages from the same source.
6 spooler Guide
When enabled, the spooler will count the messages as they are received and calculate
the number of messages during the defined time window. When the message limit is
breached, the messages are discarded and optionally dispatched with a modified
message subject.
The message number is calculated based on a sliding time window with 1-second
resolution.
spooler Configuration
Note that it is only possible to modify the configuration parameters of the spooler on a
Robot, not on a Hub.
The Setup tab
General tab
Field
Description
General
Chapter 1: spooler 7
Field
Description
Check interval
Specifies how often the spooler checks the database for messages waiting for to be
forwarded to the hub. E.g. 30 seconds means that the spooler looks for and sends
queued messages each 30th second.
Note that this parameter may be overridden by the Flush option (see below).
Message lifetime
Specifies for how long messages are stored in the spooler database before they are
deleted.
Connection duration
Specifies for how long time the spooler as a maximum is connected to the database at
each interval.
Message bulk limit
Specifies the number of messages to transfer on each post request to the hub. This field
should be used when the communications channel between spooler and hub is limited
by bandwidth and/or latency.
If the bulk functionality is not supported by the hub, the default transfer mode (one
message on each request) will be used.
Message queue size
limit (KB)
Specifies the maximum size of message queue (in KB). Every hour, the Spooler will check
the size of message queue and reduce it to specified limit by removing the oldest
messages in the queue.
Log level
Sets the level of details written to the log file. Log as little as possible during normal
operation to minimize disk consumption, and increase the amount of detail when
debugging.
Log size
Sets the maximum size for the log file. Once the log file reaches this size, it is renamed to
_spooler.log and a new log file is created.
8 spooler Guide
Postponed delivery tab
Field
Description
Enable postponed
delivery
Select this option to override the check interval above. With this option checked,
queued messages will be forwarded to the hub as soon as one of Flush limits specified
is breached.
Flush timeout
Queued messages will be forwarded to the hub on interval as specified here.
Flush priority
Queued messages will be forwarded to the hub as soon as the spooler receives a
message with the priority level specified or higher is received from a probe.
Max. queue size
Queued messages will be forwarded to the hub as soon as the number of messages
exceeds the number specified here.
Storm protection tab
Field
Description
Message Storm
Protection
Enabling this functionality will allow the spooler to monitor incoming messages and
detect situations where the message flow is not as per the pre-defined expectations.
This will protect the central messaging components (hub, nas, data_engine, etc.) in
case an abnormally large amount of messages is generated on the robot.
Chapter 1: spooler 9
Field
Description
Protection mode
Determines how the spooler will monitor the incoming messages. The following values
are supported:
■
none: storm protection is turned off
■
total: storm protection is enabled on the total amount of messages
■
by probe: messages for each probe are counted separately, so that if a storm is
detected, only the messages for the detected probe will be discarded.
■
by severity: messages for each severity level are counted separately, so that if a
storm is detected only the messages for that particular severity level will be
discarded. Note that Quality of Service messages are sent at level information.
■
by subject: messages for each message subject are counted separately, so that if a
storm is detected only the messages for that particular subject will be discarded.
The most commonly used subjects originating from a robot are alarm,
QOS_DEFINITION and QOS_MESSAGE.
The time period (in seconds) within which messages are counted.
T
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Number of messages
If the number of messages within the defined time window exceeds the value set here,
the spooler will consider this a storm situation and will start discarding messages.
Alarm severity on
message storm detect
The alarm severity on the alarm message that is sent when a storm situation is
detected. This message is sent instead of any messages exceeding the defined number
of messages limit. The message is resent at an interval equal to the defined time
window.
Alarm severity on
message storm over
Once the spooler detects that the message storm is over, it sends an alarm message.
The Alarm message text will include the number of messages discarded throughout
the storm situation.
Send discarded
messages with
‘discarded_’ subject
prefix
When a storm is detected, messages received will not be sent normally, instead they
will be discarded. In other words not added to the queue.
This option allows the discarded messages to be sent anyway, but with a modified
subject.
This allows you to monitor the discarded messages separately, without the messages
causing problems in e.g. nas or data_engine.
10 spooler Guide
Field
Description
Allows you to specify a prefix other than the default ‘discarded_’.
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Chapter 1: spooler 11
Field
Description
These profiles allow you to specify different storm detection criteria for specific items.
SRight-click options are New profile, Edit profile and Remove profile. Note that the
tprofile name must exactly match the item for which you want to override the default
o
storm detection criteria.
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12 spooler Guide
The Status tab
Field
Description
Flush status
Connection Status
An indication of the spooler’s connection status (towards the hub).
- Green indicates a normal situation
- Red indicates an error
- Yellow indicates a message storm situation
Robot
The name of the Robot hosting the spooler probe.
Domain
The name of the Domain to which the Robot belongs.
Hub Address
The address of the hub (<ip-address>:CA Portal) that the Robot/spooler is hooked up
against.
Messages in Queue
The number of messages currently in queue.
Messages Sent
The number of messages sent since the last time the spooler was activated.
Messages Discarded
The number of messages that have been discarded because of a detected message
storm since the last time the spooler was activated.
Chapter 1: spooler 13
Field
Description
Messages Expired
This field indicates the number of messages that have been stored in the spooler
database for a longer period than the specified Message Lifetime (see the Setup tab)
without being transferred to the hub. The number of messages sent since the last
time the spooler was activated.
Last Connection
The last time the spooler was connected to the hub in order to forward messages.
Connection Errors
The number of times the spooler failed to connect to the hub since the last time the
spooler was activated.
The Storm statistics tab
14 spooler Guide
The Storm Statistics tab will only be enabled when you turn on the Message Storm
Protection. Please refer to Storm protection tab for details.
This tab will display the current storm status and (when one of the protection modes by
probe, by severity or by subject is selected) a counter for each of the different items
found.
The current count indicates the number of messages currently in the time window. The
Time window and Number of messages columns show the storm protection limit for the
item.
In addition, there are fields, which display the time of the first message, the highest
message number (watermark) and the time the highest number occurred.
On right-clicking in this tab, a context menu appears with options Create/Edit protection
properties and Clear protection properties.
Create/Edit protection properties allows you to add or modify Storm property profiles;
whereas as Clear protection properties option allows you to remove Storm property
profiles directly from this window. Please refer to The Setup tab section for details.
Chapter 1: spooler
6
spooler Configuration................................................................................................................................................... 7
The Setup tab ........................................................................................................................................................ 7
The Status tab ..................................................................................................................................................... 13
The Storm statistics tab ....................................................................................................................................... 14
Chapter 1: spooler 15