What is the Fastest way to read event log on remot

问题:

I am working on an application which reads eventlogs(Application) from remote machines. I am making use of EventLog class in .net and then iterating on the Log entries but this is very slow. In some cases, some machines have 40000+ log entries and it takes hours to iterate through the entries. what is the best way to accomplish this task? Are there any other classes in .net which are faster or in any other technology?

回答1:

Man, I feel your pain. We had the exact same issue in our app.

Your solution has a branch depending on what server version you're running on and what server version your "target" machine is running on.

If you're both on Vista or Windows Server 2008, you're in luck. You should look at System.Diagnostics.Eventing.Reader.EventLogQuery and System.Diagnostics.Eventing.Reader.EventLogReader. These are new in .net 3.5.

Basically, you can build a query in XML and ship it over to run on the remote computer. Maybe you're just searching for events of a specific type, or maybe just new events from a specific point in time. The search runs on the remote machine, and then you just get back the matching events. The new classes are much faster than the old .net 2.0 way, but again, they are only supported on Vista or Windows Server 2008.

For our app when the target is NOT on Vista/Win2008, we downloaded the raw .evt file from the remote system, and then parsed the file using its binary format. There are several sources of data about the event log format for .evt files (pre-Vista), including link text and an article I recall on codeproject.com that had some c# code.

Vista and Windows Server 2008 machines use a new .evtx format that is a new format, so you can't use the same binary parsing approach across all versions. But the new EventLogQuery and EventLogReader classes are so fast that you won't have to. It's now perfectly speedy to just use the built-in classes.

回答2:

Event Log Reader is horribly slow... too slow. WTF Microsoft?

Use LogParser 2.2 - Search for C# and LogParser on the Internet (or you can use the log parser commands from the command line). I don't want to duplicate the work already contributed by others.

I pull the log from the remote system by having the log exported as an EVTX file. I then copy the file from the remote system. This process is really quick - even with a network that spans the planet (I had issues with having the log exported to a network resource). Once you have it local, you can do your searches and processing.

There are multiple reasons for having the EVTX - I won't get into the reasons why we do this.

The following is a working example of the code to save a copy of the log as an EVTX: (Notes: "device" is the network host name or IP. "LogName" is the name of the log desired: "System", "Security", or "Application". outputPathOnRemoteSystem is the path on the remote computer, such as "c:\temp\%hostname%.%LogName%.%YYYYMMDD_HH.MM%.evtx".)

    static public bool DumpLog(string device, string LogName, string outputPathOnRemoteSystem, out string errMessage)
    {
        bool wasExported = false;
        string errorMessage = "";
        try
        {
            System.Diagnostics.Eventing.Reader.EventLogSession els = new System.Diagnostics.Eventing.Reader.EventLogSession(device);
            els.ExportLogAndMessages(LogName, PathType.LogName, "*", outputPathOnRemoteSystem);
            wasExported = true;

        }
        catch (UnauthorizedAccessException e)
        {
            errorMessage = "Unauthorized - Access Denied: " + e.Message;
        }
        catch (EventLogNotFoundException e)
        {
            errorMessage = "Event Log Not Found: " + e.Message;
        }
        catch (EventLogException e)
        {
            errorMessage = "Export Failed: " + e.Message + ", Log: " + LogName + ", Device: " + device;
        }
        errMessage = errorMessage;
        return wasExported;
    }

回答3:

A good Explanation/Example can be found on MSDN.

EventLogSession session = new EventLogSession(Environment.MachineName);

// [System/Level=2] filters out the errors
// Where "Log" is the log you want to get data from.
EventLogQuery query = new EventLogQuery("Log", PathType.LogName, "*[System/Level=2]");

EventLogReader reader = new EventLogReader(query);

for (EventRecord eventInstance = reader.ReadEvent();
    null != eventInstance;
    eventInstance = reader.ReadEvent())
{
    // Output or save your event data here.
}

When waiting 5-20 minutes with the old code this one does it in less than 10 seconds.

回答4:

Maybe WMI can help you:

WMI with C#

回答5:

Have you tried using the remoting features in powershell 2.0? They allow you to execute cmdlets (like ones to read event logs) on remote machines and return the results (as objects, of course) to the calling session.

回答6:

You could place a Program at those machines that save the log to file and sends it to your webapplication i think that would be alot faster as you can do the looping local but im not sure how to do it so i cant ive you any code :(

回答7:

Maybe that the remote computers could do a little bit of computing. So this way your server would only deal with relevant information. It would be a kind of cluster using the remote computer to do some light filtering and the server would the the analysis part.