I have implemented AgentX using mib2c.create-dataset.conf ( with cache enabled)
In my snmd.conf :: agentXTimeout 15
In testtable.h file I have changed cache value as below...
#define testTABLE_TIMEOUT 60
According to my understanding It loads data every 60 second.
Now my issue is if the data in data table is exceeds some amount it takes some amount of time to load it.
As in between If I fired SNMPWALK it gives me “no response from the host” If I use SNMPWALK for whole table and in between testTABLE_TIMEOUT occurs it stops in between and shows following error (no response from the host).
Please tell me how to solve it ? In my table large amount of data is present and changing frequently.
I read some where:
(when the agent receives a request for something in this table and the cache is older than the defined timeout (12s > 10s), then it does re-load the data. This is the expected behaviour.
However the agent does not automatically release the local cache (i.e. call the 'free' routine) as soon as the timeout has expired.
Instead this is handled by a regular "garbage collection" run (once a minute), which will free any stale caches.
In the meantime, a request that tries to use that cache will spot that it's expired, and reload the data.)
Is there any connection between these two ?? I can’t get this... How to resolve my problem ???
Unfortunately, if your data set is very large and it takes a long time to load then you simply need to suffer the slow load and slow response. You can try and load the data on a regular basis using snmp_alarm or something so it's immediately available when a request comes in, but that doesn't really solve the problem either since the request could still come right after the alarm is triggered and the agent will still take a long time to respond.
So... the best thing to do is optimize your load routine as much as possible, and possibly simply increase the timeout that the manager uses. For snmpwalk, for example, you might add -t 30 to the command line arguments and I bet everything will suddenly work just fine.
Related
I have been running my JMeter script with the following setup
Users: 100
Loop Controller: 5
I used Loop Controller on the http request where transactions are needed to iterate.
My question is, there is a particular request which is searching where after 5 successful search the proceeding searches displayed “Customer API. Unable to establish connection”
Please see image below:
1 First Image displays lower load time while second image displays higher load time
It looks like you discovered a bottleneck in your application or at least it is not properly configured for high loads. Almost a minute response time for transfering 600 kilobytes is not something I would expect from a well-behaved application.
The error message you're getting is very specific so I would recommend checking your application logs as the very first step. The remaining steps would be inspecting application and middleware configuration and ensuring that it's properly set up for high performance and it has enough headroom to operate in terms of CPU, RAM, Network, Disk, etc.
I'm load testing a system with 500 virtual users. I've kept the "Ramp-Up period (in seconds)" option to zero. So, what I understand, JMeter will hit the system with 500 virtual users all at the same time. Please correct me if I'm wrong here.
Now, the summary report shows the average response time for the first page is ~100 seconds!. Which is more than a minute and a half of wait time. But while the JMeter is running, I manually went to the same page/url using a browser and didn't have to wait for that long. It was not even close, the page response was almost immediate for me.
My question is: is there any known issue for the average response time of the first page? Is it JMeter which is taking long to trigger that many users?
Thanks in advance.
--Ishtiaque
There is no issue in Jmeter related to first page response time.
Summary Report shows all response time details in Milliseconds, the value "100" seconds have you converted milliseconds to seconds?
Also in order to make sure that 500 users hit concurrently, use Synchronizing Timer.
Hope this will help.
While the response times will be accurate, you need to consider the affect of starting so many threads at once on both your server and your client.
500 threads to start at once is not insignificant n the client. If your server has the connections, it will start 500 threads as well.
Ramping over a period of time is more realistic loadwise, but still not really indicative of server capability until the threads have all started and settled in.
Databases can also require a settling in period which can affect response times.
Alternative to ramping is introducing a random wait at the start of each thread before firing the first sample. You can then choose not to ramp over time, but still expect resources on the client to suddenly come under load and change the settings if you hit limits. This will make the entire run much more realistic of typical behaviour. However, you need to determine if your use cases are typical.
Although the heap size is increased, i notice there is still longer time as compared to actual response time. Later i realised it was the probe effect (the extra time a tool generates due to test execution)
I'm running Coldfusion8 and have a cfc, that loops through a set of database records.
Each record contains two fields image path and image file. I'm constructing a path for every image, upload it to a temp folder, resize and then store it to S3.
Depending on the number of records, this may take quite some time and I have not been able to successfully finish the upload cycle with larger sets of images (eventually times out).
I'm already settings my timeout threshold to 5000, but it still does not seem enough.
I can pick up where I left, because I'm keeping a media log to check against, before uploading to S3. This way I can finish the task, but I need to trigger this function 5x to upload 400 items.
Question:
Is there way to avoid a timeout without setting (in S3 case) httptimeout to some 50000000? And would it make sense to run this in a CFTHREAD or will this be a problem if the user leaves the import page while the system is still uploading?
Thanks for some insights.
You can use a CFthread to perform the task, but make sure you LOCK THE SCOPE! otherwise you could end up running this memory intensive proccess several times over and kill the server, you only want this proccess running once at a time if its so intensive.
You have other options though, if this is not something that your application users will need to run and its a one-off proccess your doing, you could set a scheduled task with an exceedingly long timeout to run overnight, when the server is not very high use, This allows you to set the timeout independently to the application so the rest of the application is unaffected by global timeout changes.
Another option is, if this is something users will be doing semi-regularly then a thread which pushes a notification via email, log or other means (Ajax or Websockets) letting the user know they're task is complete. This has the upside that timeouts can be changed, calculated on the amount of data to be proccessed dynamically at thread generation. However, if your not careful you can overload your server with many threads proccessing large datasets (plus log file read-write locks will be harder to manage).
I would encourage you though, to take this away and see what solution works for you and post your final solution so others can see what the outcome is.
Hope this helps.
This is kind of a 2 part question
1) Is there a max number of HttpWebRequests that can be run at the same time in WP7?
I'm going to create a ScheduledTaskAgent to run a PeriodicTask. There will be 2 different REST service calls the first one will get a list of IDs for records that need to be downloaded, the second service will be used to download those records one at a time. I don't know how many records there will be my guestimage would be +-50.
2.) Would making all the individual record requests at once be a bad idea? (assuming that its possible) or should I wait for a request to finish before starting another?
Having just spent a week and a half working at getting a BackgroundAgent to stay within it's memory limits, I would suggest doing them one at a time.
You lose about half your memory to system libraries and the like, your first web request will take another nearly 20%, but it seems to reuse that memory on subsequent requests.
If you need to store the results into a local database, it is going to take a good chunk more. I have found a CompiledQuery uses less memory, which means holding a single instance of your context.
Between each call I would suggest doing a GC.Collect(), I even add a short Thread.Sleep() just to be sure the process has some time to tidying things up.
Another thing I do is track how much memory I am using and attempt to exit gracefully when I get to around 97 or 98%.
You can not use the debugger to test memory limits as the debug memory is much higher and the limits are not enforced. However, for comparative testing between versions of your code, the debugger does produce very similar result on subsequent runs over the same code.
You can track your memory usage with Microsoft.Phone.Info.DeviceStatus.ApplicationCurrentMemoryUsage and Microsoft.Phone.Info.DeviceStatus.ApplicationMemoryUsageLimit
I write a status log into IsolatedStorage so I can see the result of runs on the phone and use ScheduledActionService.LaunchForTest() to kick the off. I then use ShellToast notifications to let me know when the task runs and also when it completes, that way I can launch my app to read the status log without interrupting it.
Tyler,
My 2 cents here.
I don't believe there is any restriction on how mant HTTPWebequests you can spin up. These however have to be async, off course, and may be served from the browser stack. Most modern browsers including IE9 handle over 5 concurrently to the same domain; but you are not guaranteed a request handle immediately. However, it should not matter if you are willing to wait on a separate thread, dump your content on to the request pipe & wait for response on yet another thread. This post (here) has a nice walkthrough of why we need to do this.
Nothing wrong with this approach either, IMO. You're just going to have to wait until all the requests have their respective pipelines & then wait for the responses.
Thanks!
1) Your memory limit in a PeriodicTask or ResourceIntensiveTask is 5 MB. So you definitely should control your requests really careful. I dont think there is a limit in the code.
2)You have only 5 MB. So when you start all your requests at the same time it will terminate immediately.
3) I think you should better use a ResourceIntensiveTask because a PeriodicTask should only run 15 seconds.
Good guide for Multitasking features in Mango: http://blogs.infosupport.com/blogs/alexb/archive/2011/05/26/multi-tasking-in-windows-phone-7-1.aspx
I seem to remember (but can't find the reference right now) that the maximum number of requests that the OS can make at once is 7. You should avoid making this many at once though as it will stop other/system apps from being able to make requests.
I have developed my own SNMP service, and i want to plot a graph of an OID provided.
So, i have created a graph in Cacti.
-) It is showing device up.
-) It is creating rrd file. (RRDTool says OK).
-) Showing the graph, but it's empty.
But when I check it, say
rrdtool fetch <rrd file> AVERAGE
it shows me nan for all the values. The monitored OID has value 47 and i have set min=0 and max=100.
I am using Cacti appliance by rpath:
http://www.rpath.org/ui/#/appliances?id=http://www.rpath.org/api/products/cacti-appliance
Still, I can't show value on graph..
Where is the problem? Can anyone please tell me?
First of all, use Cacti's "Rebuild Poller Cache" function under the Utilities menu.
If that didn't work ,check if the RRD file is actually updating with new data.
To do this use the command:
rrdtool last [filename.rrd]
This will output the last time (in unix timestamp) that a new value has been inserted into the RRA file which you can compare to the current time that date +%s will output.
If it's not updating with data then you should change the cacti log level to DEBUG via the settings page on Cacti's web UI and look for appropriate messages.
If the poller couldn't get the data then it's usually an issue relating to connectiviy/SNMP.
You can further check issues as such by manually polling the specific OID on that host:
snmpwalk -c[SNMP COMMUNITY] -v2c [HOSTNAME OR IP ADDRESS] 1.3.6.1.2.1
You can use the above command and OID (1.3.6.1.2.1) just to see if you're getting a reply.
If that worked then you should change the command from snmpwalk to snmpget and the OID to the actual OID you're trying to poll and retry.
If the RRD is updating with new data but you're still getting NaN in your graphs then I suggest looking into the heartbeat and step values of the data source (via the data template) in relation to your polling interval and poller cronjob interval.
These values determine how many times the RRD file will miss data before inserting a NaN.
The cronjob calls the cacti poller to start performing it's polling cycle.
The poller interval is the actual time that the poller will wait between two polling cycles if it was indeed invoked in time by the cronjob.
So for 1 minute polling (on the poller and the cronjob) you will have to use a step of 60 (seconds) and a heartbeat of 120.
For 5 minutes polling, the step will be 300 and the heartbeat will be 600.
This is mainly caused by someone changing the poller interval on the settings page.
Gandalf from the Cacti forums wrote a nice Guide that you can use and further help can be found on Cacti forums.
Good luck! :)
Maybe cacti doesn't have the needed permissions to access the rrd file and your test was done with a user who has the required permissions, for example root?
Are you sure you have collected enough data?
If your RRD has a step of 1 minute, and your first RRA has a consolidated count of 1 (1cdp=1pdp), then you should collect data for at least (step x ( count + 1 )) seconds before you expect to see any data in the graph. Make sure you are collecting data at least as often as the step size.
If you collect data for 10 min and nothing shows up, then make sure you are actually collecting the data, make sure the values you get are within range, and that they are being used. Check the last modification time on the RRD file. Print out the values before you update to verify they are what you think they are.
You should double check the range Cacti is plotting in. I moved the values in the graph filter and spotted a little chunk of data in the graphs, then you just have to adjust it.