Category: sysadmin
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discard/TRIM for SSD with etx4, LVM, LUKS encrypted devices
Cheatcheat to enable TRIM (discard) in a SSD with ext4, lvm and luks encrypted devices. Ext4 In /etc/fstab add discard as option of the ext4 filesystem. If you are using LVM: In /etc/lvm/lvm.conf change issue_discards from 0 to 1. For Luks crypto: Append option discard in /etc/crypttab. Line should end like luks,discard. . Append rd.luks.options=discard…
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Create root user on Gitlab, when you can’t define root’s password
When Gitlab it’s installed, the first access to the site allows you to define the password for the root (administrative) account. But due to a bug/error when I installed it on Debian testing (Stretch) i always git the standard registration box, not for root. Googling, i found i was not the only one bitten by…
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Hints on package removal for Debian-based systems
The following hints are on how to identify packages that can be removed from a Debian-based system. My motivations on trimming the system are optimal use of resources, the less packages the better from my point of view, but never less than needed. As well as reduce potential attack vectors. – Delete downloaded packages cache:…
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packet filter
SYN flood http://en.wikipedia.org/wiki/SYN_flood echo 1 > /proc/sys/net/ipv4/tcp_syncookies XMAS packet http://en.wikipedia.org/wiki/Christmas_tree_packet iptables -A INPUT -p tcp –tcp-flags ALL ALL -j DROP SMURF http://www.nordu.net/articles/smurf.html echo 1 > /proc/sys/net/ipv4/icp_echo_ignore_broadcasts TCP Null http://lab.gsi.dit.upm.es/semanticwiki/index.php/TCP_Null_Scan iptables -A INPUT -p tcp –tcp-flags ALL NONE -j DROP
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Comparison of Linux schedulers (BFS vs stock)
graysky’s performance comparison of current schedulers (BFS vs stock scheduler) across various hardware in this comprehensive pdf: cpu_schedulers_compared.pdf
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Five Best Linux Distributions
Five Best Linux Distributions @ http://lifehacker.com/5904069/five-best-linux-distributions