Log2Zram

Usefull for IoD / maker projects for reducing SD, Nand and Emmc block wear via log operations. Uses Zram to minimise precious memory footprint and extremely infrequent write outs.

Log2Zam is a lower write fork https://github.com/azlux/log2ram based on transient log for Systemd here : A transient /var/log

Can not be used for mission critical logging applications where a system crash and log loss is unaceptable. If the extremely unlikely event of a system crash is not a major concern then L2Z can massively reduce log block wear whilst maintinaing and extremely tiny memory footprint.

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Menu

1. Install
2. Upgrade
3. Customize
4. It is working ?
5. Uninstall

Install

curl -Lo log2ram.tar.gz https://github.com/azlux/log2ram/archive/master.tar.gz
tar xf log2ram.tar.gz
cd log2ram-master
chmod +x install.sh && sudo ./install.sh
cd ..
rm -r log2ram-master

REBOOT before installing anything else (for example apache2)

Upgrade

You need to stop log2ram (service log2ram stop) and start the install.

Customize

variables :

In the file /etc/log2ram.conf, there are three variables:

• SIZE: defines the size the log folder will reserve into the RAM (default is 40M).
• USE_RSYNC: Can be set to true if you prefer ´rsync´ rather than ´cp´. I use the command cp -u and rsync -X, I don’t copy the all folder every time for optimization.
• MAIL: Disables the error system mail if there is not enough place on RAM (if set to false)

refresh time:

By default Log2Ram writes to the HardDisk every hour. If you think this is too much, you can make the write every day by moving the cron file to daily: sudo mv /etc/cron.hourly/log2ram /etc/cron.daily/log2ram.

It is working?

You can now check the mount folder in ram with (You will see lines with log2ram if working)

# df -h
…
log2ram          40M  532K   40M   2% /var/log
…

# mount
…
log2ram on /var/log type tmpfs (rw,nosuid,nodev,noexec,relatime,size=40960k,mode=755)
…

Testing

sudo service log2ram reload

Checks PRUNE_LEVEL < available free space if true will move and clean /var/log/oldlog to hdd.log

sudo logrotate -vf /etc/logrotate.conf

Force the daily logrotate with verbose output

If you have issue with apache2, you can try to add apache2.service next to other services on the Before parameter in /etc/systemd/system/log2ram.service it will solve the pb

The log for log2ram will be written at: /var/log/log2ram.log

Compressor name	Ratio	Compression	Decompress.
zstd 1.3.4 -1	2.877	470 MB/s	1380 MB/s
zlib 1.2.11 -1	2.743	110 MB/s	400 MB/s
brotli 1.0.2 -0	2.701	410 MB/s	430 MB/s
quicklz 1.5.0 -1	2.238	550 MB/s	710 MB/s
lzo1x 2.09 -1	2.108	650 MB/s	830 MB/s
lz4 1.8.1	2.101	750 MB/s	3700 MB/s
snappy 1.1.4	2.091	530 MB/s	1800 MB/s
lzf 3.6 -1	2.077	400 MB/s	860 MB/s

Now, muffins for everyone!

Uninstall :(

(Because sometime we need it)

chmod +x /usr/local/bin/uninstall-log2ram.sh && sudo /usr/local/bin/uninstall-log2ram.sh

Also /var/oldlog contains the pruned logs from install delete if not required (prob not)