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--- linux:prepare:prepare [2016/02/14 11:28]
niziak
+++ linux:prepare:prepare [2023/07/30 08:53] (current)
niziak
@@ Line 3: / Line 3: @@
 ===== Basic =====
-=== Disable console beep ===
+==== default EDITOR ====
-To disable console annoying beep:
- * System wide by removing PC Speaker module:
 <code bash>
-rmmod pcspkr
+sudo update-alternatives --list editor
-sudo echo "blacklist pcspkr" > /etc/modprobe.d/pcspkr-blacklist.conf
+sudo update-alternatives --config editor
 </code>
-=== Usefull software ===
+==== set umask ====
-<code bash>sudo apt-get install wireshark cups</code>
-<code bash>sudo usermod -G lp,lpadmin,dialout,sudo,audio,video,netdev,vboxusers,wireshark,kismet,i2c user_login</code>
+In file: ''~/.profile''
+  * ''umask 002'' (default), RW for user, RW for group and R for others - create dirs as 775 and files as 664
+  * ''umask 022'' (default for root), 755 and 644
+  * ''umask 077'' only RW for user, not other access
+  * ''umask 007'' RW for user, RW for group
-=== parallel packers ===
+**NOTE!:** Problem appears with non default user umask and ''sudo'' command usage.
-<code bash>sudo apt-get install pigz pbzip2 pxz lbzip2</code>
+After sudo umask is still set to the user umask, which is correct.
+But can lead to some unpredicted behavior i.e. installing system-wide packages - new file will be created with incorrect umasks (user umask).
-To force using parallel packers system-wide:
+To prevent this:
-<code bash>
+<file | /etc/sudoers>
-ln -s /usr/bin/lbzip2 /usr/local/bin/bzip2
+Defaults        umask_override
-ln -s /usr/bin/lbzip2 /usr/local/bin/bunzip2
+Defaults        umask=0022
-ln -s /usr/bin/lbzip2 /usr/local/bin/bzcat
-ln -s /usr/bin/pigz /usr/local/bin/gzip
-ln -s /usr/bin/pigz /usr/local/bin/gunzip
-ln -s /usr/bin/pigz /usr/local/bin/zcat
-ln -s /usr/bin/pixz /usr/local/bin/xz
-</code>
-or use bash aliases:
-<file | .bashrc>
-alias gzip='pigz'
-alias gunziip='unpigz'
-alias bzip2='pbzip2'
-alias bunzip2='pbunzip2'
-alias xz='pxz'
 </file>
-=== add i386 architecture ===
+==== add i386 architecture ====
 <code bash>
@@ Line 47: / Line 37: @@
 </code>
-=== etckeeper ===
+==== NTP: allow time corrections bigger than 1h ====
+  - Disable systemd time service: ''systemctl disable --now systemd-timesyncd''
+  - Install ''ntpdate'' and ''ntp''
+  - Edit ''/etc/default/ntp'' and add ''-g'' argument.
+  - Switch RTC to UTC time:
 <code bash>
-apt-get install git
+timedatectl set-local-rtc 0
-git config --global user.name "my name"
+ntpd -gxn
-git config --global user.email myemail@address.pl
+hwclock --systohc
-apt-get install git-cola etckeeper kdiff3
 </code>
-=== Disable PC speaker ===
+==== Disable PC speaker ====
 <code bash>
 echo "blacklist pcspkr" > /etc/modprobe.d/nobeep.conf
 </code>
-=== resolv.conf ===
+==== resolv.conf ====
 <code bash>apt-get install resolvconf</code>
@@ Line 71: / Line 67: @@
 === Polish & locales ===
 <code bash>
+dpkg-reconfigure keyboard-configuration
 apt-get install console-data
 dpkg-reconfigure console-data
@@ Line 90: / Line 87: @@
-For logitech devices there are additional packets:
+Remember to set [[sw:libreoffice#paper_format]]
+==== set cfq/deadline scheduler ====
+<file | /etc/udev/rules.d/60-schedulers.rules>
+ACTION=="add|change", KERNEL=="sd[a-z]", ATTR{queue/rotational}=="1", ATTR{queue/scheduler}="cfq"
+ACTION=="add|change", KERNEL=="sd[a-z]", ATTR{queue/rotational}=="0", ATTR{queue/scheduler}="deadline"
+</file>
+<code bash>cat /sys/block/sd*/queue/scheduler</code>
+=== single queue schedulers ===
+There are 2 queues, one for read & one for write operations.
+  * **none** is just a First In First Out standard queue of I/O operations.
+  * **cfq** (Completely Fair Scheduling) is similar to the Round Robin algorithm and basically allots a fixed execution time for each I/O operation (they are implemented as a circular queue)
+  * **deadline** is like a priority queue with an aging concept. Basically it adds a deadline for each I/O operation & implements a priority queue
+=== block multi-queue schedulers ===
+Supported in kernel >=4.12. It is disabled by default.
+To use multi-queue schedulers compile kernel with **CONFIG_SCSI_MQ_DEFAULT=y** or pass parameter **scsi_mod.use_blk_mq=1** in boot loader.
+[[https://www.thomas-krenn.com/en/wiki/Linux_Multi-Queue_Block_IO_Queueing_Mechanism_(blk-mq)|Linux Multi-Queue Block IO Queueing Mechanism]]
+<file | /etc/udev/rules.d/60-schedulers.rules>
+ACTION=="add|change", KERNEL=="sd[a-z]", ATTR{queue/rotational}=="1", ATTR{queue/scheduler}="bfq"
+ACTION=="add|change", KERNEL=="sd[a-z]", ATTR{queue/rotational}=="0", ATTR{queue/scheduler}="mq-deadline"
+</file>
 <code bash>
-sudo apt-get install lomoco solaar
+sudo udevadm control --reload
+sudo udevadm trigger
+cat /sys/block/sd*/queue/scheduler
 </code>
-[[https://wiki.archlinux.org/index.php/Logitech_Marble_Mouse]]
+==== Disable console beep ====
-=== NTP: allow time corrections bigger than 1h ===
+To disable console annoying beep:
-  - Edit /etc/default/ntp and add "-s" argument.
+ * System wide by removing PC Speaker module:
-  - Ordered List ItemInstall ntpdate and ntp
-  - Ordered List ItemSwitch RTC to UTC time:
 <code bash>
-timedatectl set-local-rtc 0
+rmmod pcspkr
-ntpd -qg
+sudo echo "blacklist pcspkr" > /etc/modprobe.d/pcspkr-blacklist.conf
-hwclock --systohc
+</code>
+===== Usefull software =====
+<code bash>sudo apt-get install wireshark cups</code>
+<code bash>sudo usermod -G lp,lpadmin,dialout,sudo,audio,video,netdev,vboxusers,wireshark,kismet,i2c user_login</code>
+==== parallel packers ====
+<code bash>sudo apt-get install pigz pbzip2 pxz lbzip2</code>
+To force using parallel packers system-wide:
+<code bash>
+ln -s /usr/bin/lbzip2 /usr/local/bin/bzip2
+ln -s /usr/bin/lbzip2 /usr/local/bin/bunzip2
+ln -s /usr/bin/lbzip2 /usr/local/bin/bzcat
+ln -s /usr/bin/pigz /usr/local/bin/gzip
+ln -s /usr/bin/pigz /usr/local/bin/gunzip
+ln -s /usr/bin/pigz /usr/local/bin/zcat
+ln -s /usr/bin/pixz /usr/local/bin/xz
+</code>
+or use bash aliases:
+<file | .bashrc>
+alias gzip='pigz'
+alias gunziip='unpigz'
+alias bzip2='pbzip2'
+alias bunzip2='pbunzip2'
+alias xz='pxz'
+</file>
+some benchmarks (i7-3770K), BTRFS FS +NoCOW attrib
+^ command    ^ user time ^ size ^ comments ^
+|pbzip2 -1   | 4m12       | 694M |         |
+|pbzip2 -5   | 4m59       | 683M |         |
+|pbzip2 -9   | 6m25       | 679M | default |
+|pigz -0     | 0m32       | 3,5G | no compression |
+|pigz -1     | 0m52       | 727M |         |
+|pigz -2     | 0m48       | 723M |         |
+|pigz -6     | 1m18       | 698M | default |
+|pxz -0      | 3m30       | 660M |         |
+|pxz -3      | 5m00       | 636M |         |
+|pxz -6      | 11m19      | 571M | default |
+==== etckeeper ====
+<code bash>
+apt-get install git
+git config --global user.name "my name"
+git config --global user.email myemail@address.pl
+apt-get install git-cola etckeeper kdiff3
 </code>
+==== mandb ====
+Disable mandb updates after apt:
+<code bash>echo "set man-db/auto-update false" | debconf-communicate; dpkg-reconfigure man-db</code>

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