Kernel sysctl configuration file for Linux
The following is suitable for dedicated web server, mail, file server etc.
place file in /etc/sysctl.d/60-zercle.conf
and run sysctl --system
Kernel tuning for linux server
How to deleting large number of files in Linux
When try to delete directory that contain a ton of files with rm -rf target_dir/ that very slow or even crashes, so we have other way to delete that directory with perl or rsync Continue reading “How to deleting large number of files in Linux”
Let’s Encrypt wildcard certificates with Certbot’s DNS plugins
Certbot’s DNS plugins which can be used to automate obtaining a wildcard certificate from Let’s Encrypt’s ACMEv2 server now are not available in some official repository.
IF you don’t want to wait, you can use these plugins now by use certbot from source.
Continue reading “Let’s Encrypt wildcard certificates with Certbot’s DNS plugins”
Run Go (golang) CLI from docker
Go is an open source programming language that makes it easy to build simple, reliable, and efficient software. Now we can run it from golang’s official docker ( https://hub.docker.com/_/golang/ ) with current terminal path.
Install docker and change data directory
Docker is a useful container but by default all docker’s stuff will place in /var/lib/docker in many case this will share with root disk space. For easy to maintain disk space we just change docker’s directory to separate disk or path. Continue reading “Install docker and change data directory”
Alternative dd with pv for faster speed and show progress
dd command
# run as root dd if=/dev/source of=/dev/target bs=16M
pv command
# run as root apt-get install pv pv < /dev/source > /dev/target # or run with sudo sudo bash -c 'pv < /dev/source > /dev/target'
Tuning Linux ZFS
Edit /etc/modprobe.d/zfs.conf
# Set use max memory at half of system memory (ex. 4GB/2) options zfs zfs_arc_max=2147483648 # Increase scrub/resilver worker options zfs zfs_vdev_scrub_min_active=24 options zfs zfs_vdev_scrub_max_active=64 # Increase sync write options zfs zfs_vdev_sync_write_min_active=8 options zfs zfs_vdev_sync_write_max_active=32 # Increase sync reads options zfs zfs_vdev_sync_read_min_active=8 options zfs zfs_vdev_sync_read_max_active=32 # Increase async reads options zfs zfs_vdev_async_read_min_active=8 options zfs zfs_vdev_async_read_max_active=32 # Increase async write options zfs zfs_vdev_async_write_min_active=8 options zfs zfs_vdev_async_write_max_active=32
Save and reboot system to active configuration
Mirror http(s) (s)ftp(s) with lftp
Install lftp
#!/usr/bin/env bash apt update && apt -y full-upgrade apt -y install lftp exit 0
Mirror from remote to local
lftp http://mirror.remote.site/src-path -e "mirror -e -c -P=4 . /local/target-path; bye"
Explain
lftp remote_url/path -e [command]
mirror [option] source target
-e delete different files
-c continue transfer
-P=[number] number of parallel connections
Enable IPv4 and IPv6 on Zimbra Collaboration
Work around nginx proxy IPv6 fix
sed -i 's| ipv6only=off||g' /opt/zimbra/conf/nginx/templates/nginx.conf.*
Get current settings
su zimbra zmprov gs `zmhostname` | grep -i ipmode
Get public IP
# IPv6 curl http://v6.ipv6-test.com/api/myip.php # IPv4 curl http://v4.ipv6-test.com/api/myip.php
Enable IPv4 and IPv6
zmprov ms `zmhostname` zimbraIPMode both zmprov ms `zmhostname` "127.0.0.0/8 [::1]/128 IPv4/32 [IPv6]/128" /opt/zimbra/libexec/zmiptool zmcontrol restart