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ZNC Memory Usage
This page is intended to give users an idea and rough estimate of how much memory ZNC needs to run. Other users are asked to provide anecdotal reports which include memory usage as well as other relevant information.
Various factors can affect ZNC memory usage, including:
- Number of channels (across all users on a ZNC instance)
- Average saved buffer size of each channel
- Whether the AutoClearChanBuffer setting is used. Note that when it's enabled, the configured buffer size can be confusing, because the real buffer size is often zero.
- Query Buffers (if ZNC 1.5 or later)
- Loaded modules (number, type, and function)
- Number of users
- System architecture (x86, x86-64, etc.)
Note: These are anecdotal reports, which are personal experiences of other ZNC users/administrators. These reports are not in any way verified, nor are any of them the least bit scientific. If exact resource usage figures are important, performing your own testing is highly recommended. As always, YMMV.
The following list doesn't include a list of modules used in each case for the sake of brevity. However, module use could have a meaningful effect on memory usage.
There are multiple ways of determining memory usage, but here is the method used for more than half of the entries listed:
$ ps aux --sort -rss | grep znc | awk '{print $1" "$2" "$6}' | column -t
Example output:
zero-one 903 32144 darthga+ 18346 5848 zero-one 15469 4652 mindy 1467 1652 hammy 1478 1560
This is the username who owns the process, followed by the PID, and the resident memory usage in kiloBytes.
| ZNC Version | Memory Usage | Number of channels | Number of networks | Average Buffer Size | AutoClearChanBuffer | Number of Users | System Arch |
|---|---|---|---|---|---|---|---|
| 1.4 | 60.9 MB | About 260 | About 2,000 | Yes, mostly | 9 | x86-64 (Debian 7.7) | |
| 1.4 | 27.8 MB | About 100 | About 100 | Yes, mostly | 8 | x86-64 (Debian 7.7) | |
| 1.5 | 12.1 MB | About 20 | 4 | About 850,000 | Yes | 1 | x86-64 (Slackware 14.1) |
| 1.5 | 7.3 MB | About 30 | 2 | About 4,290,032,704 | Yes | 4 | x86-64 (Ubuntu 13.10) |
| 1.6.5 | 160 MB | About 100 | 5 | 50 | Yes | 1 | x86-64 (Debian 8) |
| 1.6.5 | 57 MB | About 100 | 2 | 50 | Yes | 2 | x86-64 (Debian 8) |
| 1.7.x-git* | 324.75 MB | Over 200 | About 50 - 100 | Yes | 57 | x86-64 (Ubuntu 17.04) | |
| 1.7.x-git | 50.2 MB | 53 | 2 | About 1,000,000 | Yes | 2 | x86-64 (Ubuntu 14.04.5 LTS) |
| 1.7.x-git [ZNC-Linker bot] | 7.9 MB | 2 | 1 | About 50 | Yes | 1 | x86-64 (Ubuntu 14.04.5 LTS) |
| 1.7.x-git | 4.7 MB | 9 | 1 | About 500 | Yes | 1 | x86-64 (Ubuntu 14.04.5 LTS) |
| 1.7.x-git | 10.3 MB | 10 | 1 | About 50 | Yes | 1 | x86-64 (Ubuntu 16.04.2 LTS) |
| 1.7.x-git | 7.7 MB | 7 | 1 | About 50 | Yes | 1 | x86-64 (Ubuntu 16.04.2 LTS) |
| 1.6.5* | 250 MB | 160 | 30 | About 50 | Yes, mostly | 30 | x86-64 (FreeBSD 10) |
| 1.6.x-git | 72.1 MB | 566 | 68 | About 2,000 on most channels, 50 on about a third of them. | Yes, mostly | 6 | x86-64 (Debian 7.11) |
| 1.6.4 | 41 MB | 110 | 22 | 300 | No | 1 | x86-64 (openSUSE Leap 42.3) |
| 1.7.x-git | 30 MB | 31 | 10 | 50 | Yes | 2 | x86-64 (Arch) |
| 1.6.5 | 48 MB | 82 | 11 | 1500 | No | 1 | x86-64 (Debian 9.3) |
| 1.6.5 | 20.68 MB | 12 | 5 | 112.5 | No | 1 | x86-64 (CentOS 7) |
| 1.8.x-git | 145.7 MB | 276 | 10 | About 500,000 | Yes | 2 | x86-64 (Ubuntu 14.04.5 LTS) |
| 1.7.1 | 703.4 MB | 4354 | 693 | About 100 | Yes, mostly | 433 | x86-64 (Arch) |
| 1.6.5 | 20 MB | 25 | 4 | 5000 | No | 1 | x86-64 (FreeBSD 11) |
| 1.7.4 | 89 MB | 953 | 106 | 50 | Yes | 73 | x86-64 (Debian 8) |
Versions with " * " are modified versions.