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103 lines
4.1 KiB
Markdown
103 lines
4.1 KiB
Markdown
# Performance Settings (Boost)
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The Performance Settings sub-tab in Cacti contains settings that
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can help improve the life of your Cacti server and significantly
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increase the live and lower the I/O wait of your Cacti system
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through caching of RRDfile disk writes.
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It will also reduce the number of CPU cores require to render
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Cacti **Graphs** due to it's image cache mechanism.
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We will explain how these settings work briely in the next
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two sections. However, there is a more detailed guide in
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the [Advanced Topics](Boost.md). Please refer to that guide
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as well.
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## On-demand RRD Update Settings
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These are settings to place RRDfile updates into a database
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table and cache them. Then, on a periodic basis dump those
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updates to disk at once. This will reduce the overall wear
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and tear of your disks, and reduce the time periods where
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disk I/O will be higher. You can see the available settings
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in the image below.
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The settings include:
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- **Enable On-demand RRD Updating** - This check-box will enable
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on-demand updating and caching of unwritten updates. If you
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disable it, the poller must first clear the cache before it
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can be fully disabled. So, disabling is not immediate after
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it has been activated for some time.
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- **How Often Should Boost Update All RRDs** - As it says, what
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is the desired frequency of performing updates. The idea with
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boost is to reduce the amount of disk I/O, so if your poller
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frequency/interval is say 5 minutes, you may want to cache
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a few hours of updates.
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- **Number of Boost Processes** - For systems with shared disk
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where I/O performance is impacted by file system
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overhead or latency, the concurrent boost process
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setting comes in handy. Cacti will spawn the number
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of collectors specified by this setting.
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- **Maximum Records** - This is a threshold in cache records
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that if that number is exceeded, the cache will immediately
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begin to be cleared. This setting works together with the
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**How Often** setting.
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- **Maximum Data Sources Items Per Pass** - Cacti will count
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the number of distinct data sources in your system, and then
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divide it by this amount, and then make X number of passes
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through the data. If you have 1M **Data Sources** and 100M
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records in the cache, and set the setting to 100k, Cacti
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will make 10 passes through the **Data Sources** each pass
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processing approximately 10M cache entries.
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- **Maximum Argument Length** - This is the longest RRDtool
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update command to use. Most Linux systems allow for a very
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long command line. It's advisable to use something less
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than 32k though as some versions of RRDtool have problems
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with longer command lines.
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- **Memory Limit for Boost and Poller** - In a modern Cacti
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system, unless you have more than a million **Data Sources**
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the default of 1GB is likely enough.
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- **Maximum RRD Update Script Run Time** - This is the longest
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to allow the cache clearing script to run before notifying
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the primary Cacti admin. The process will be allowed to
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continue to run, but will issue a WARNING.
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- **Enable direct population of poller_output_boost table** -
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Originally a `spine` only setting, this setting is now
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supported in both `spine` and `cmd.php`. Instead of having
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to move records inside of the **Data Collector** Cacti
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simply makes two writes, one into the main output table
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and another into the boost table. Cacti has to write
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to the primary output table as some plugins require that
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data to be there immediately for fault management.
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- **Boost Debug Log** - If non-blank and points to a
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location that is writable, Cacti will log the RRDtool
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syntax used to update the RRDfiles.
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## Image Caching
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The Image Caching setting on the Performance sub-tab
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basically defined where to store time sensitive
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images caches of your various Cacti **Graphs**. These
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Cached images only live for a few minutes, but can
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be consumed by multiple users simultaneously.
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The image of the settings is shown below. They are
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fairly self explanatory.
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---
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Copyright (c) 2004-2026 The Cacti Group
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