eG Monitoring
 

Measures reported by CtxSDXInstancesTest

NetScaler SDX supports multiple NetScaler instances on a single hardware appliance. An administrator can effectively partition the physical box into as many as 16 virtual instances. This helps enterprises running specific virtual versions of the SDX with different settings, configurations and software versions tuned to work with specific services within an enterprise.

If any of these virtual NetScaler instances is rendered unavailable, then users may be denied access to the critical services associated with that instance. Moreover, if an instance is poorly sized with CPU, memory, and network resources, or is utilizing resources excessively, the performance of that instance and the other instances supported by that SDX will naturally deteriorate for want of adequate resources. This is why, the availability, resource configuration, and resource usage of each virtual NetScaler instance should be monitored and administrators proactively notified of any inaccessibility or resource contention on any instance. This is what the CtxSDXInstancesTest test does! 

This test auto-discovers the VPX instances that the target NetScaler SDX appliance supports and reports the availability of each instance. If the test alerts to an instance unavailability, you can use this test to once again verify why that instance is inaccessible - is it because the instance is down or the VM hosting that instance is halted? The test also monitors the resource configuration of each instance and the percent resource consumption of every instance; in the process, the test points you to resource-hungry instances, and thus The uptime of each instance is also reported, so that administrators can promptly detect unscheduled instance reboots and unplanned instance downtime.

Outputs of the test : One set of results for each VPX instance supported by the target NetScaler SDX.

Measurement Description Measurement Unit Interpretation
Vm_state Indicates the current state of the VM hosting this VPX instance.   The values that this measure can report and their corresponding numeric values have been listed in the table below:

Numeric Value Measure Value
100 Running
0 Halt

Note:

By default, this measure reports the above-mentioned Measure Values to indicate the current state of a VM. However, in the graph of this measure, the Measure Values will be represented using their corresponding numeric equivalents only.

 
Instance_state Indicates the current state of this VPX instance.   The values that this measure can report and their corresponding numeric values have been listed in the table below:

Numeric Value Measure Value
100 Up
0 Down

When a user complains that a NetScaler VPX instance is inaccessible, then check the value of this measure for that instance to determine whether/not that instance is up and running. If it is, then check the value of the Vm_state measure for the same instance to determine whether the Virtual machine is running or halted.

Note:

By default, this measure reports the above-mentioned Measure Values to indicate the current state of a VPX instance. However, in the graph of this measure, the Measure Values will be represented using their corresponding numeric equivalents only.
Cpu_usage Indicates the percentage of allocated CPU used by this VPX instance. Percent A value close to 100% is indicative of excessive CPU usage by the VPX instance.

Compare the value of this measure across instances to know which instance is over-utilizing CPU. You may want to consider increasing the CPU allocation to that instance.
Vm_memory_total Indicates the total memory of this VPX instance. MB  
Memory_usage Indicates the percentage of memory used by this instance. Percent A value close to 100% is indicative of excessive memory usage by the VPX instance.

Compare the value of this measure across instances to know which instance is over-utilizing memory. You may want to consider increasing the memory allocation to that instance.
Input_throughput Indicates the bandwidth consumed by incoming traffic to this VPX instance. Mbps  
Output_throughput Indicates the bandwidth consumed by outgoing traffic from this VPX instance. Mbps  
Total_throughput Indicates the total bandwidth consumption of this instance. Mbps This measure is the sum of the Input_throughput and Output_throughput measures of the VPX instance. If this value increases consistently, it is indicative of excessive bandwidth consumption by the instance.

You may want to periodically compare the value of Total_throughput (i.e., actual throughput) with the value of the Assign throughtput (i.e., allocated throughput measure of an instance. This will reveal if bandwidth sizing for that instance has been done on the basis of its real-time bandwidth consumption. Based on these observations, you can choose to reconfigure the bandwidth allocation to the instance. For example, you may have set the throughput allocation mode as fixed for an instance, and may have hard-allocated throughput resources to that instance. Later however, by tracking changes to the value of the Total_throughput measure, you may discover that the hard limit is often violated, causing the SDX appliance to drop traffic. In such a case, you may want to consider changing the allocation mode to burstable. When using the burstable option, options are available to allow over commitment of throughput above the set throughput value that is required.
Assign_throughput Indicates the throughput assigned/allocated to this instance. Mbps
Http_request Indicates the rate at which this instance receives HTTP requests. Requests/Sec  
Ha_master_state Indicates whether this instance is the primary or secondary instance in an HA setup. The values that this measure can report and their corresponding numeric values are listed in the table below:

Numeric Value Measure Value
100 Primary
0 Secondary

Note:

By default, this measure reports the above-mentioned Measure Values to indicate the master state of the instance. However, in the graph of this measure, the Measure Values will be represented using their corresponding numeric equivalents only.
Ha_synch Indicates whether/not HA synchronization is enabled on this instance. The values that this measure can report and their corresponding numeric values are listed in the table below:

Numeric Value Measure Value
100 Yes
0 No

Note:

By default, this measure reports the above-mentioned Measure Values to indicate the HA sync status of an instance. However, in the graph of this measure, the Measure Values will be represented using their corresponding numeric equivalents only.
L2_enabled Indicates whether/not L2 mode is allowed on this instance.   In Layer 2 (L2) mode, a NetScaler instance acts as a learning bridge and forwards all packets for which it is not the destination. Some features, such as Cloud Bridge, require that L2 mode be enabled on the NetScaler instance. With L2 mode enabled, the instance can receive and forward packets for MAC addresses other than its own MAC address. However, if a user wants to enable L2 mode on a NetScaler instance running on an SDX appliance, the administrator must first allow L2 mode on that instance.

If the L2 mode is allowed on an instance, then this measure will report the value Yes. If the L2 mode is not allowed, then this measure will report the value No for that instance.

The values that this measure can report and their corresponding numeric values are listed in the table below:

Numeric Value Measure Value
100 Yes
0 No

Note:

By default, this measure reports the above-mentioned Measure Values to indicate the L2 mode status. However, in the graph of this measure, the Measure Values will be represented using their corresponding numeric equivalents only.
Assign_packets Indicates the rate at which this instance can receive packets. Packets/Sec  
Noof_ssl_cores_up Indicates the number of SSL cores that are currently up and running. Number The term ‘SSL Core’ is used to represent an assignment in hardware of a number of Cavium cores. The SDX appliance uses these Cavium cores to accelerate SSL traffic in hardware.
Noof_ssl_cores Number Instances cannot share SSL cores. Any SSL cores that are allocated at the time of provisioning an instance are dedicated to that instance.

Memory and SSL Cores are interlinked, so when assigning each SSL core it will be necessary to assign 1Gb of memory per core.
Rebooted Indicates whether/not this instance was rebooted during the last measurement period.   The values that this measure can report and their corresponding numeric values are listed in the table below:

Numeric Value Measure Value
1 Yes
0 No

Note:

By default, this measure reports the above-mentioned Measure Values to indicate the reboot status of an instance. However, in the graph of this measure, the Measure Values will be represented using their corresponding numeric equivalents only.
Uptime Indicates the time period for which this instance was up since the last time this test ran. Secs If the instance has not been rebooted during the last measurement period and the agent has been running continuously, this value will be equal to the measurement period. If the instance was rebooted during the last measurement period, this value will be less than the measurement period of the test. For example, if the measurement period is 300 secs, and if the instance was rebooted 120 secs back, this metric will report a value of 120 seconds.  The accuracy of this metric is dependent on the measurement period - the smaller the measurement period, greater the accuracy.
Total_uptime Indicates the total time for which this instance was up since its last reboot.   This measure displays the number of years, months, days, hours, minutes and seconds since the last reboot. Administrators may wish to be alerted if an instance has been running without a reboot for a very long period. Setting a threshold for this metric allows administrators to determine such conditions.