Newsletter 7.0.5: May update


We are coming back with new set of information regarding Energy Logserver – starting with currently latest version - 7.0.5. This time we would like to turn your attention to some new data management capabilities we’ve introduced as well as our response to CentOS 7&8 dispute. Hope you will find it helpful!


Data Management Capabilities


While log retention due to regulatory compliance is something we see in almost every organizations we work with – the scope of what part from log message to store - varies.

With newly introduced „archiving the selected fields” you are able to select the exact fields from the log message, which you would like to save in your storage.

Just create new „Archive” task and filter the names you want to include in the report:

This way you can seriously optimize you log storage & archives searching speed!


Now, when deleting an object, in “object permission” you can mark related objects to be deleted at the same time. This is made to ease-up the governance time with our solution. Remember when you had to manually remove each visualization from saved dashboard?

It is not the case anymore!

No when you go to each:
Saved search -> Visualization -> Dashboard  - you can delete dashboard with all related objects.



Newly added scheduler helps you to stay compliant with re-occurring reporting requests. This feature is helpful when you are looking to:

Automate certain reporting task (e.g. monthly application performance report)

Prepare report from certain upcoming date (with scheduler, you don’t have to remember)

Dump the raw data in scheduled manner

This feature can be a great addition to both – compliance and governance related function set.


Deployment updates


Our installation support is now additionally possible for Oracle Linux7/8, Scientific Linux 7, Centos Stream (and also originally for Centos7/8 and RedHat7/8). We decided to introduce new implementation possibilities due to recent issues with Linux Centos distribution. You can see more in following article: CentOS Linux is dead—and Red Hat says Stream is “not a replacement"


As your fellow technical team – we will be happy to discuss this ground-breaking announcement and help you prepare for the future!

Newsletter 7.0.5: New version and enhanced reporting


New version has arrived! Energy Logserver is currently at version 7.0.5. We've planned this update to be smaller one, with mainly optimization and stabilization changes. But it turned out that we’ve added significant features on which we were working for some time. Below are some of highlights.


Major changes


We’ve added SUNBURST IOC detection to Energy Logserver. SUNBURST is serious threat that can be used to steal sensitive information from organization and even take control of infected systems. This attack is very serious and it is worth to monitor it’s activity. Energy Logserver has been equipped with predefined alerts that can be used to detect SUNBURST. You can read more here

Alert through syslog

Feature has been added to Alert UI. You can select alerting method as syslog message. This is very useful for integrating Energy Logserver with many different solutions, which are capable of receiving data or signal through syslog. You can select host, port, protocol, severity and facility of this notification method.

National character support

Energy Logserver has now full national character support. This makes it completely ready for any custom data from uncommon sources. Every module of Energy Logserver is prepared to process and function with 100% efficiency with such data.

Reporting enhanced

Reports and exports has been enhanced with additional information. Now you can see who created report or export task and when. Report scheduler has been optimized and moved to the same tab as report creator. With this update you have even more control and information about Energy Logserver users. This is next step in our direction to make Energy Logserver user management be as useful and easy as possible.


We’ve also tackled one of most confusing topics in elasticsearch: Keyword and Text string types – what is the difference.

Feel free to read short article here:

If you find that interesting, then few words about optimization should be something you want to know 🙂

Read more on our blog:


Stay safe and happy searching!

Energy Logserver team

Few words about optimization

While working with elasticsearch it’s impossible to avoid the topic of shard optimization. Sooner or later every user of a more complex system will have to take up this topic. An unoptimized elasticsearch environment can result in slow data indexing, returning responses, and even unstable performance of the entire environment.

The sooner we understand where this problem comes from and the sooner we address it, the better. Planning elasticsearch shard policies is essential to ensure a long-lasting and stable cluster performance. It is also worth remembering that shards are nothing else than the Lucene engine on the basis of which elasticsearch was created.


What is shard?

Index is built with shards and we divide them into primary and replica. Each shard holds some part of the data stored in the index, so the set of primary shards in the index will act as RAID 0. Additionally, each primary shard can have its 1:1 replica. This guarantees data availability in the event of a cluster failure. If any primary shard becomes unavailable, its replica takes his place.



Often times, the elasticsearch environments that receive the data are not properly managed in terms of space. This means that the data released into the environment remain there for a long time, somehow forgotten. Indexing large amounts of data without proper management can quickly consume even huge disk resources. The reason for this is that the replicas are 1: 1 copies of the primary shards.

Holding an index (e.g. 100GB) of 4 shards and each of them has its own three replicas means that we have a total of 15 shards (4 primary + 12 replicas) and 400 GB of data. It is not hard to see how inattention can lead to a quick full disk in such a scenario.

Optimization consists in categorizing data and assigning them an appropriate number of shards and replicas. Of course, each replica taken means a greater susceptibility to permanent data loss in the event of a failure. It is known, however, that not every index is critical and for those with lower priority it is worth considering how many replicas they require.



Elasticsearch is software made in java. The assigned heap is therefore crucial for the proper functioning of the environment. Incorrectly scheduling the server's memory resources can contribute to a serious failure due to insufficient memory.

How to judge how much memory an elasticsearch node requires It depends on the size of the cluster and the amount of data we collect. Elasticsearch holds a lot of data in memory for quick access. It is recommended that an elasticsearch node does not have more than 25 shards (primary and replicas) per 1 GB of memory in the heap. It is worth noting that elasticsearch is not able to limit this for us. This is one of the fundamental steps of an administrator to monitor the number of shards per heap memory.



When it comes to query optimization, there is no secret that the main element is the structure of the query and the scope of data on which the query is triggered. In other words: 100GB data will be responded faster than 500GB data.

The more complicated the query and the more data is run, the later we will get the answer. Therefore, it is important to balance the relationship between the number of shards and their size.

It is recommended that one shard contains between 20GB and 40GB of data. Therefore, if we have an index of 100GB of data, it is worth allocating a total of 4 shards primary. Replicas are not included in this optimization procedure as they hold 1: 1 copies of the data of the primary shards.



The above aspects show that although elasticsearch is a powerful tool and one of the best engines for managing large amounts of data, it still needs careful attention in terms of optimization. Good planning of the indexes and shards structure will allow you to enjoy a stable and very efficient cluster environment.

Text vs Keyword

There are two types of data in elasticsearch that are often troublesome for people inexperienced in working with the system - Keyword and Text. Both types are a kind of string, but elasticsearch interprets them differently, so you can perform different operations on them.


How file type is made?

In general, the type of field is determined by the template. It is a instruction for creating indexes in elasticsearch - including field mappings. If a given template does not clearly specify what type of field the given field should be, elasticsearch will by default create dynamic mapping for both Keyword and Text. However, it is not recommended to work in that manner, due to the disk space that can be saved by planning assigned types to fields.


Inverted index

To understand the importance of the problem, look at the inverted index in elasticsearch[1] . It is a specific way in which the system saves data and thanks to this solution, elasticsearch is very fast in returning large amount of dokuments even on a big time scale.

The inverted index is similar to the index in some books. At the end of the book you can find a list of words with information on which pages these words appear on. Elasticsearch does exactly the same for each word that mentions which document it is in.


For example. let's look at document with id "my-document". It has a field of "address" with value of "Wiejska 20, Warsaw".
POST "localhost:9200/my-index/_doc/my-document" -d'
"address" : "Wiejska 20, Warsaw"

Below is a presentation of how elasticsearch sees it in the inverted index for both types

Difference in query

Elasticsearch first checks the inverted index for a match when it receives a query. If it finds them, it displays the documents that match that query. Therefore, if we query elasticsearch for the value "Warsaw", a document with the Keyword type may not return the result because the value is literally "Wiejska 20, Warsaw". The opposite is true in the case of the Text type - because the field content has been analyzed, elasticsearch is able to find single words in the inverted index and return the answer in the form of a document.

Of course, there are still different kinds of search queries to Elasticsearch, and depending on which ones are used, you may get different results. This point, however, does not directly touch upon the differences in the field types themselves.



The differences between the two types are significant. We generally use keyword types for constant values in the data that we do not want to analize, eg country name, application name, etc. We use the Text type when we need to use the full text search power, eg in the message field that contains the original message from the system.


[1] In truth, the inverted index is a aspect of the Apache Lucene engine on which Elasticsearch was developed. A shortcut was used to make understanding of the problem easier.

Newsletter 7.0.4 Feb update: Wiki


Second month went really fast here at Energy Logserver. We are full of motivation, as it seems that each day bring new challenges to tackle.
We are currently working on few game changing modules for Energy Logserver. Right now, we’ve finished polishing and updating existing functionalities and are happy to share more information with you. For presentation of interesting features, please register to our webinar, more information below:

Webinar Energy Logserver 7.0.4 – User views and advanced permissions
25.03.2021 10:00 AM Warsaw

Custom views
Roles now can have assigned modules to permissions, which allow to create dedicated views. This advanced but easy to use feature allows for such use cases as:
- Creating dedicated view for analytical teams, who doesn’t need to see raw data.
- SOC views, who need to see clear information and need to be able to switch between information from different modules.
- Create clear and separate views for different department, even if data is still centralized within one environment.

Energy Logserver now has built-in wiki solution. This allows you to keep easy to read documentation and information about your infrastructure. By using Wiki with Energy Logserver you make sure that information are easy to read and available only to those who should have access to it. This module give opportunity to provide new functionalities and use cases in Energy Logserver eg. CMDB, automatic documentation creation based on collected data and much more.

Windows Event Forwarding (WEF) is common topic within environment with large Windows infrastructure. Idea is to have option to share data without installing agent. Windows Event Collector (WEC) is therefore required to be also Windows machine, which cause some problems to maintain and monitor. We’ve developed standalone solution which is intended to gather data from Windows to Linux system!
Energy Event Collector is designed to use native Windows technology but expand its functions from closed environment and allow more flexible approach.
See more information here:

Automatic archiving data is important aspect of managing storage space inside Energy Logserver. This module was introduced with previous newsletter. We believe it is worth to highlight how important archive management is. We are constantly improving and optimizing archive module functions.

Stay safe and happy searching!
Energy Logserver team

Vulnerability Scanner integration

Vulnerabilities are common problem in IT community. Some are serious, other – not so much. Most important is to know if any vulnerabilities are present in our systems, how critical they are and how they can be fixed. There are tools that can help you do get that information, called vulnerability scanners.

Vulnerability scanners check your systems and applications if they have any of known exploits or backdoors. Similar to antivirus software, these programs have their own databases which needs to be updated regularly. Reports of such scan can be however long and hard to analyze.

Energy Logserver brings good news for all who want to increase visibility and security correlation over their environment. We are now integrating with leading solutions: Qualys, and of course OpenVAS 🙂

New dashboard dedicated for vulnerability scanners also has been added on top of that integration. It means that we can not only gather data and integrate with vulnerability scanners but also we give you the ability to see exactly what has been detected in your infrastructure and correlate it with data from different sources.

Interactive dashboard is equipped with list of found problems and recommended solutions, list of top hosts with color-coded vulnerabilities detected and many more.

If you are interested in this functionality or your version of Energy Logserver does not have it implemented, reach out to our team or at sales[at]

Newsletter 7.0.4 and Webinar: archive mdoule


Happy New Year from Energy Logserver Team
We are glad to announce that Energy Logserver is currently at version 7.0.4.
This version brings some amazing changes along with new module – archive, which lets you manage automatic archiving data. More about it below.

First thing. If you are interested in seeing new features in action, we would like to invite you to our upcoming webinar!

Webinar Energy Logserver 7.0.4 – Archive module
21.01.2021 10:00 AM Warsaw

Major changes

New module: Archive
Allows to configure automatic archiving of selected indexes and send them to selected destination. More than that, with this module you are able to search on archived data without moving them back to the system. Restoration process also is really simple – just choose archives that you’d like to restore and it’s done!

Improved agent management module
Agent management looks not only better but now it also gives you option to remotely restart desired agent. Also you are now able to monitor/change custom configurations, not related to Energy Logserver agents.

New default integration
We’ve added new integration to Energy Logserver. Now Energy Logserver 7.0.4 by default has integration with vulnerability scanners and brings amazing dashboard to visualize all the data you’ve gathered.

Upgraded alerts
Alerts module now support name change of existing alerts (we know that lots of you were waiting for that ;)) but more than that, you can group alerts together, like Windows related, etc. Furthermore we’ve added GUI support for notification on Slack and OP5 Monitor. And finally – we’ve added two new options:
• Calendar, which allows you to manage time of alert notifications based on cron format
• Escalate, which escalate alarm after specific time.

For full list of changes, visit:

If you are looking for some interesting use cases for Energy Logserver, you will find some below as well as you can visit our website:

Detecting and alerting user login events after office hour

Detecting and alerting Abnormal Network Traffic Pattern

Detecting and alerting DDoS attacks in Energy Logserver

Stay safe and happy searching!
Energy Logserver team

Webinar: Incident management in Energy Logserver – from SOC to Analytics


We hope that you are all staying safe and healthy in these interesting times. At Energy Logserver we are working non-stop to deliver best quality features for you. That is why we would like to share with you what is new.

Energy Logserver is currently at 7.0.3 version. In this version we strongly focused on event correlation and alerting along improved internal auditing. We want to highlight most interesting aspects of this version.


Major changes

Improved types of alerts:

  • Chain – possibility to tailor each individual rules one after another. The rule is triggered when threshold is met and the expected data sequence occurs. Example: detection of failed logins followed by success.
  • Logical – activates when selected alerts are triggered with defined logic. Example: detection of at least 3 failed logins OR root login AND 2 service configuration changes.

Agent module:

With Energy Logserver 7.0.3 expect new look of Agents Module, responsible for central management. We’ve improved reliability, better control for agents state and others – all available from user interface.


Familiar with Skimmer, our internal monitoring process? New version provides more cluster health-check metrics, like:

  • Indexing rate – shows EPS in the system
  • Expected data nodes – Energy Logserver measures its performance and calculates how much data nodes it requires for optimal workflow.
  • Heap usage – shows assigned memory usage for every component group in Energy Logserver infrastructure
  • Disc space – monitor disc space usage, so you can see how much space is left for the data and you’ll never run into troubles.
  • and others..

If you are not familiar with Skimmer, then you definitely should check it out!


Our community is giving us new challenging questions, which we are addressing. We are happy to work along those who share love for monitoring software. Solving issues together is very satisfying. Here are some highlights:

How to deal with oversized Kafka documents in Logstash?

How to remove duplicated or not important messages from syslog?

Why processing time of logstash DNS filter is slow?


Webinars coming soon:

Incident management in Energy Logserver - from SOC to Analytics

10.12.2020 starting 11 AM CET

Click here to register:


During this webinar we will look at how to search data for errors and anomalies. We will create incidents and look at how to work with Energy Logserver from two perspectives - operational and analytical with dashboards.


Stay safe and happy searching!

Energy Logserver team

How to remove duplicated or not important messages from syslog?

Issue description

we all know this entry in the syslog:
... last message repeated ... times

can it somehow be easily ruled out?

Issue solution

Yes, they can. There are many ways to do so and below is only one such example:

filter {
  if [source] == "/ var / log / messages" {
    if [message] =~ / last message repeated [0-9] + times / {
      drop {}

DNS logstash filter is slow

Issue description


I've used the DNS filter on the logstash, but i can clearly see that the indexing speed has decreased by adding resolve.
Does it have to be so slow?

Logstash config from documentation:

filter {
  dns {
    reverse => [ "source_host", "field_with_address" ]
    resolve => [ "field_with_fqdn" ]
    action => "replace"

Issue solution


In older versions of logstash (2018 *), after using the cache_size / failed_cache_size directive, there was a bug that prevented parallel cache polling.

A very nice analysis with performance graphs was carried out by the git user named robcowart:

A ready config to use below - please note that full performance is obtained when the cache is full with data.
It's also worth using fast dns, e.g.

  # dns resolve
  dns {
    reverse => [ "hostname" ]
    action => "replace"
    nameserver => ["", ""]
    hit_cache_size => 131072
    hit_cache_ttl => 900
    failed_cache_size => 131072
    failed_cache_ttl => 900

  # filter performance
  metrics {
    meter => "events"
    add_tag => "metric"

output {
  if "metric" in [tags] {
    stdout {
      codec => line {
        format => "DNS filter rate: %{[events][rate_1m]}"