dovecot.index.cache: Cannot allocate memory

If you get this error you may assume it is a lack of memory, which it could be, but more likely it is the default memory size of 256M. The file in this example was about 350M big which of course exceeds the virtual memory limits. This makes sense in smaller mail servers but if you have large amounts of users or e-mails this limit should be bumped. Check your default size limit: doveconf -n | grep -E 'vsz_limit|service imap' default_vsz_limi........

LSI MegaRAID in Linux Ubuntu / Centos Tutorial Setup Guide megacli

Usually when I come across a system like this, Ijust flash the firmware to an IT mode so we get just an AHCI system with JBOD, but sometimes it is not practical for remote systems or if we fear that flashing is too risky if something goes wrong. In this case, we unfortunately have to use LSI/Broadcom proprietary CLI tools (megacli) to even make the drives visible. Step 1 - Download MegaCLI The official broadcom packages lack .deb packages and only have .rpm for........

Linux Howto Zip Multiple Files and Directories

zip is useful to share files across multiple platforms. A simple way if you want to zip all pdfs: zip Labs.zip *.pdf If you want to zip everything in the current directory and subdirectories do this: zip -r stuff.zip *........

Centos 7 Reallocate logical volume space to another

Do you hate how Centos 7 defaults to allocating most of your valuable space to /home even though it is a production server? Here is a quick guide on how to take back that space live, while online (of course make sure you have backups just in case something goes wrong!): First we will reduce our home dir by 100G: lvreduce -L -100G /dev/mapper/centos-home WARNING: Reducing active and open logical volume to ........

ffmpeg Linux Mint download, compile and install howto

#if you have nvidia make sure you install the nvidia-cuda-toolkit so hardware acceleration can be used wget http://ffmpeg.org/releases/ffmpeg-3.3.2.tar.bz2 tar -jxvf ffmpeg-3.3.2.tar.bz2 cd ffmpeg-3.3.2/ ./configure --disable-yasm install prefix /usr/local source path ........

How to create openssl md5 password hash to use in /etc/shadow using bash

Very useful in embedded and other non-standard deployments. The above makes a random salt of 14 random characters from /dev/urandom (you can change the -14 to whatever number of characters you want for your salt). openssl passwd -1 -salt `< /dev/urandom tr -dc _A-Z-a-z-0-9 | head -c${1:-14};echo;` YourPassword Output: $1$eW-ScuyL$f/iKMJ5mbJ..7bSzvX6EO0 How To Create Password Has........

Openvz OOM Centos Issue Memory Config Settings Solution

Linux box13. 2.6.32-042stab076.5 #1 SMP Mon Mar 18 20:41:34 MSK 2013 x86_64 x86_64 x86_64 GNU/Linux even setting privvmpages to a specific setting DOES not affect "free -m" in containers. This is probably a kernel issue 23:36:29 up 159 days, 7:12, 4 users, load average: 0.42, 0.44, 0.33 [root@box13 ~]# free -m total&n........

Country List Names in HTML Select From

This is useful for developing a lot of applications, I'm putting it here to keep it handy for myself and hopefully others: Choose CountryCanadaJapanUnited StatesUnited KingdomAfghanistan........