Advanced Linux - using TCP BBR
I've looked at BBR and it certainly looks like a great innovation in network performance. That said I only recommend its use right now by advanced Linux admins with a pressing need for the improved performance, and then only after serious load testing on non critical network links.
For everyone else I recommend you wait until it is integrated into your Linux distribution and the mainline kernel. That way you are not messing with your vendor's highly tuned and optimized kernel configuration and you're getting something tested and integrated into the system as a whole.
#Linux #SysAdmin #Networking
https://www.cyberciti.biz/cloud-computing/increase-your-linux-server-internet-speed-with-tcp-bbr-congestion-control/
Showing posts with label SysAdmin. Show all posts
Showing posts with label SysAdmin. Show all posts
Friday, 21 July 2017
Wednesday, 5 July 2017
Watch out for security patches for anything you use that uses GnuPG's crypto library!
Watch out for security patches for anything you use that uses GnuPG's crypto library!
That may actually be more things than you think. Things like routers, phones or phone apps, etc. and not just on Linux. GnuPG is widely used cross platform.
#linux #Security #SysAdmin #Windows
http://www.theregister.co.uk/2017/07/04/gnupg_crypto_library_cracked_look_for_patches/
That may actually be more things than you think. Things like routers, phones or phone apps, etc. and not just on Linux. GnuPG is widely used cross platform.
#linux #Security #SysAdmin #Windows
http://www.theregister.co.uk/2017/07/04/gnupg_crypto_library_cracked_look_for_patches/
Sunday, 26 February 2017
Network bonding with Linux
Network bonding with Linux
Sysadmins have been using this trick for years to get their own, inexpensive, custom, high speed network links. A primary example is from a server to a NAS device. Or a server to a backplane switch that supports bonding.
These days there are even ways to bond ISP connections to increase bandwidth if you're lucky enough to have an ISP that supports bonding.
So read on and find out how to do network bonding on Linux.
#Linux #sysadmin #Networking
http://kerneltalks.com/other/network-bonding-teaming-configuration-in-linux/
Sysadmins have been using this trick for years to get their own, inexpensive, custom, high speed network links. A primary example is from a server to a NAS device. Or a server to a backplane switch that supports bonding.
These days there are even ways to bond ISP connections to increase bandwidth if you're lucky enough to have an ISP that supports bonding.
So read on and find out how to do network bonding on Linux.
#Linux #sysadmin #Networking
http://kerneltalks.com/other/network-bonding-teaming-configuration-in-linux/
Thursday, 3 November 2016
Linux Tips & Tricks - Mastering the command line - SED
Linux Tips & Tricks - Mastering the command line - SED
Manipulating text in files is a common daily task for any sysadmin and learning to use the powerful tools available to do this can make an administrator's life vastly easier.
One of the most common and powerful tools for doing this is 'sed'.
Here's a sed tutorial to get you started.
Also note that sed has a partner 'awk' that is equally powerful in different ways. The two are often learned and used together.
To learn more about sed and awk, check out:
http://www.theunixschool.com/p/awk-sed.html
https://quickleft.com/blog/command-line-tutorials-sed-awk/
http://docstore.mik.ua/orelly/unix/sedawk/
#Linux #Sysadmin #CommandLine
http://www.tecmint.com/linux-sed-command-tips-tricks/
Manipulating text in files is a common daily task for any sysadmin and learning to use the powerful tools available to do this can make an administrator's life vastly easier.
One of the most common and powerful tools for doing this is 'sed'.
Here's a sed tutorial to get you started.
Also note that sed has a partner 'awk' that is equally powerful in different ways. The two are often learned and used together.
To learn more about sed and awk, check out:
http://www.theunixschool.com/p/awk-sed.html
https://quickleft.com/blog/command-line-tutorials-sed-awk/
http://docstore.mik.ua/orelly/unix/sedawk/
#Linux #Sysadmin #CommandLine
http://www.tecmint.com/linux-sed-command-tips-tricks/
Tuesday, 4 October 2016
Using Network Manager from the command line
Using Network Manager from the command line
In recent years Linux has been under major assault from a young generation of Apple using, form over function loving, change for the sake of change making kiddies that have attention spans too short to bother to learn how to properly use Linux, never mind how and why things were done the way they were done on Linux and UNIX.
This led to such ridiculous situations as many Linux distros switching to Network Manager for network configuration, even before it could fully perform all of the functions of the systems it replaced. Worst of all there was, for a looong time, no way to configure it from the command line. Making it useless for any serious applications requiring for example, headless operation, remote shell administration, scripted operation, etc. Finally this was rectified with the introduction of nmcli. Though nmcli eventually offered full command line configuration functionality, it seems to have been made intentionally obtuse in it's operation and syntax, as if to punish you for wanting to use the command line instead of a GUI.
For those of you that learned Linux in recent years, under the anti CLI mentality that's become so pervasive, you may by now be advanced enough to want or need to do things from the command line anyway. Here's an article to get you started on using nmcli. Good luck and keep learning the command line.
#Linux #NetworkManager #CommandLine #SysAdmin
http://www.tecmint.com/configure-network-connections-using-nmcli-tool-in-linux/
In recent years Linux has been under major assault from a young generation of Apple using, form over function loving, change for the sake of change making kiddies that have attention spans too short to bother to learn how to properly use Linux, never mind how and why things were done the way they were done on Linux and UNIX.
This led to such ridiculous situations as many Linux distros switching to Network Manager for network configuration, even before it could fully perform all of the functions of the systems it replaced. Worst of all there was, for a looong time, no way to configure it from the command line. Making it useless for any serious applications requiring for example, headless operation, remote shell administration, scripted operation, etc. Finally this was rectified with the introduction of nmcli. Though nmcli eventually offered full command line configuration functionality, it seems to have been made intentionally obtuse in it's operation and syntax, as if to punish you for wanting to use the command line instead of a GUI.
For those of you that learned Linux in recent years, under the anti CLI mentality that's become so pervasive, you may by now be advanced enough to want or need to do things from the command line anyway. Here's an article to get you started on using nmcli. Good luck and keep learning the command line.
#Linux #NetworkManager #CommandLine #SysAdmin
http://www.tecmint.com/configure-network-connections-using-nmcli-tool-in-linux/
Thursday, 22 September 2016
Linux Tips & Tricks - using the tar command
Linux Tips & Tricks - using the tar command
tar is one of the core administration tools of the *NIX world, it's been around forever and it's still highly useful today.
Here's a link to get you started using this powerful command-line tool.
#Linux #tar #sysadmin
http://www.linuxtechi.com/17-tar-command-examples-in-linux/
tar is one of the core administration tools of the *NIX world, it's been around forever and it's still highly useful today.
Here's a link to get you started using this powerful command-line tool.
#Linux #tar #sysadmin
http://www.linuxtechi.com/17-tar-command-examples-in-linux/
Sunday, 28 August 2016
Linux Tips & Tricks:
Linux Tips & Tricks:
Surviving systemd - "Where the hell are my logs?!"
At some point even casual Linux users are going to want to have a look at their system logs for one reason or another. It's an important part of many diagnostic processes. However, most of the how to's out there on the Internet are geared towards using the UNIX style system logs that Linux used for decades until it was struck with the plague that is systemd. If your system uses systemd, and these days nearly all do, then all of your nice, easily readable and grep'able text logs are gone! What to do. Well, those logs have nearly all been replaced by a binary journal that systemd keeps in a database. To access them you'll need to learn to use journalctl which is systemd's front end to the log database. Here's a nice tutorial to get you started on the basics of using it.
For the impatient, you can type the following to see what's been logged since yesterday. Be prepared for a deluge.
From a root shell:
journalctl --since yesterday
(Note the ^ double dash)
#Linux #systemd #Logs #sysadmin
https://www.digitalocean.com/community/tutorials/how-to-use-journalctl-to-view-and-manipulate-systemd-logs
Surviving systemd - "Where the hell are my logs?!"
At some point even casual Linux users are going to want to have a look at their system logs for one reason or another. It's an important part of many diagnostic processes. However, most of the how to's out there on the Internet are geared towards using the UNIX style system logs that Linux used for decades until it was struck with the plague that is systemd. If your system uses systemd, and these days nearly all do, then all of your nice, easily readable and grep'able text logs are gone! What to do. Well, those logs have nearly all been replaced by a binary journal that systemd keeps in a database. To access them you'll need to learn to use journalctl which is systemd's front end to the log database. Here's a nice tutorial to get you started on the basics of using it.
For the impatient, you can type the following to see what's been logged since yesterday. Be prepared for a deluge.
From a root shell:
journalctl --since yesterday
(Note the ^ double dash)
#Linux #systemd #Logs #sysadmin
https://www.digitalocean.com/community/tutorials/how-to-use-journalctl-to-view-and-manipulate-systemd-logs
Monday, 22 August 2016
Linux Tips & Tricks - Bash shell pitfalls
Linux Tips & Tricks - Bash shell pitfalls
In my ongoing quest to get people to either start using the command line, or use it more effectively, here's a great little resource for using the most common Linux command shell.
#sysadmin #Linux #CommandLine #bash
Via Carlos F. Lange
http://mywiki.wooledge.org/BashPitfalls
In my ongoing quest to get people to either start using the command line, or use it more effectively, here's a great little resource for using the most common Linux command shell.
#sysadmin #Linux #CommandLine #bash
Via Carlos F. Lange
http://mywiki.wooledge.org/BashPitfalls
Thursday, 16 June 2016
Learning Linux - Make your servers more resilient with monit
Learning Linux - Make your servers more resilient with monit
Sometimes server services stop, crash, or hang and you can't be around 24/7 to monitor them, but monit can. Hence the name.
With monit you can setup a watchdog service to monitor the goings on of your Linux system and customize the reaction to each individual monitored service, file, port, etc. From logging it, to restarting it, to notifying you or all the above, monit can do it.
The article's instructions are geared towards Debian, but OpenSUSE users can install very simply by typing the following in a root shell.
zypper in monit
Enjoy.
#Linux #Sysadmin
http://www.linux-server-security.com/linux_servers_howtos/linux_monitor_services_monit.html
Sometimes server services stop, crash, or hang and you can't be around 24/7 to monitor them, but monit can. Hence the name.
With monit you can setup a watchdog service to monitor the goings on of your Linux system and customize the reaction to each individual monitored service, file, port, etc. From logging it, to restarting it, to notifying you or all the above, monit can do it.
The article's instructions are geared towards Debian, but OpenSUSE users can install very simply by typing the following in a root shell.
zypper in monit
Enjoy.
#Linux #Sysadmin
http://www.linux-server-security.com/linux_servers_howtos/linux_monitor_services_monit.html
Saturday, 21 May 2016
Limiting bandwidth hogs by application rather than by user in Linux
Limiting bandwidth hogs by application rather than by user in Linux
There are a lot of ways to do this, but Trickle does give a fairly simple way to limit applications on the fly (or globally). Unlike more traditional methods like IPtables or bandwidthd etc., this is a quick, easy, and (unless you want it to be) non permenant solution to using applications that normally hog bandwidth while allowing other applications to function smoothly. For example, downloading a big file without disrupting your YouTube cats viewing session.
Note that this article isn't for everyone. The author uses a long demonstration format to teach the concepts. Setting up ncftp and testing it before and after. But you can skim through and pickup the concepts easily enough.
My other issue with the article is the subtle backdoor Mormon Church advertising, but you can easily ignore that by just not watching the sample video.
#Linux #sysadmin #Networking #Bandwidth
http://www.tecmint.com/manage-and-limit-downloadupload-bandwidth-with-trickle-in-linux/
There are a lot of ways to do this, but Trickle does give a fairly simple way to limit applications on the fly (or globally). Unlike more traditional methods like IPtables or bandwidthd etc., this is a quick, easy, and (unless you want it to be) non permenant solution to using applications that normally hog bandwidth while allowing other applications to function smoothly. For example, downloading a big file without disrupting your YouTube cats viewing session.
Note that this article isn't for everyone. The author uses a long demonstration format to teach the concepts. Setting up ncftp and testing it before and after. But you can skim through and pickup the concepts easily enough.
My other issue with the article is the subtle backdoor Mormon Church advertising, but you can easily ignore that by just not watching the sample video.
#Linux #sysadmin #Networking #Bandwidth
http://www.tecmint.com/manage-and-limit-downloadupload-bandwidth-with-trickle-in-linux/
Sunday, 8 May 2016
Linux Tips & Tricks - Command Line school
Linux Tips & Tricks - Command Line school
For those of you old enough to remember the old phone company ads, it's time to "reach out and touch" someone. Or in this case, some files.
The touch command is another command that must be in your bag of sysadmin and user skills. While it seems like a simplistic command of little practical use, in reality it is a very powerful and useful tool.
Note: If you use an SSD with Linux, you may find touch even more useful given many distributions now disable the at-time function on SSD drives. Even if you use the preferred option of using relatime
instead of noatime in your SSD mounts, you wont have accurate at-time information for files on that drive. This can lead to circumstances where applications, scripts, or system functions may fail. In these circumstances, any kludge of a workaround will likely involve the touch command.
#Linux #Sysadmin #CommandLIne
http://www.binarytides.com/linux-touch-command/
For those of you old enough to remember the old phone company ads, it's time to "reach out and touch" someone. Or in this case, some files.
The touch command is another command that must be in your bag of sysadmin and user skills. While it seems like a simplistic command of little practical use, in reality it is a very powerful and useful tool.
Note: If you use an SSD with Linux, you may find touch even more useful given many distributions now disable the at-time function on SSD drives. Even if you use the preferred option of using relatime
instead of noatime in your SSD mounts, you wont have accurate at-time information for files on that drive. This can lead to circumstances where applications, scripts, or system functions may fail. In these circumstances, any kludge of a workaround will likely involve the touch command.
#Linux #Sysadmin #CommandLIne
http://www.binarytides.com/linux-touch-command/
Monday, 2 May 2016
Got a bunch of Linux boxen you're administering?
Got a bunch of Linux boxen you're administering?
Make life easier with DSH
DSH, or Distributed Shell, let's you handle multiple systems at once. Handy stuff.
#Linux #SysAdmin #CommandLine
http://www.tecmint.com/using-dsh-distributed-shell-to-run-linux-commands-across-multiple-machines/
Make life easier with DSH
DSH, or Distributed Shell, let's you handle multiple systems at once. Handy stuff.
#Linux #SysAdmin #CommandLine
http://www.tecmint.com/using-dsh-distributed-shell-to-run-linux-commands-across-multiple-machines/
Linux tips and tricks - Managing your $PATH
Linux tips and tricks - Managing your $PATH
As you progress as a Linux user, expand your command line skills, and take on more complex tasks, eventually you will cross paths with $PATH (see what I did there? ;')
In fact this is true on most operating systems. The system path determines where the system looks for commands you enter. This is handy when you add new applications to the system.
Here's a basic overview of checking and changing your $PATH to suit your needs. Be careful though. This has the potential to break your system or allow malware to break free of the standard Linux security restrictions so check into and understand any changes you make here before you make them. Also note that order matters. The system checks the path locations in the order they appear in the $PATH variable. This can cause system binaries to replaced by other binaries and break functionality etc.
#Linux #CommandLine #BASH #SysAdmin
http://www.tecmint.com/set-path-variable-linux-permanently/
As you progress as a Linux user, expand your command line skills, and take on more complex tasks, eventually you will cross paths with $PATH (see what I did there? ;')
In fact this is true on most operating systems. The system path determines where the system looks for commands you enter. This is handy when you add new applications to the system.
Here's a basic overview of checking and changing your $PATH to suit your needs. Be careful though. This has the potential to break your system or allow malware to break free of the standard Linux security restrictions so check into and understand any changes you make here before you make them. Also note that order matters. The system checks the path locations in the order they appear in the $PATH variable. This can cause system binaries to replaced by other binaries and break functionality etc.
#Linux #CommandLine #BASH #SysAdmin
http://www.tecmint.com/set-path-variable-linux-permanently/
Friday, 29 April 2016
Linux - command line tips & tricks
Linux - command line tips & tricks
More skills for your sysadmin bag.
#Linux #sysadmin #commandline
http://www.tecmint.com/find-top-large-directories-and-files-sizes-in-linux/
More skills for your sysadmin bag.
#Linux #sysadmin #commandline
http://www.tecmint.com/find-top-large-directories-and-files-sizes-in-linux/
Sunday, 10 April 2016
Linux Tips & Tricks - Finding the text editor for you
Linux Tips & Tricks - Finding the text editor for you
Linux is blessed with a wealth of text editors to suit every person and editing need. Here's a list of some and a guide to choosing one that's right for both you and the task at hand.
#Linux #SysAdmin #Editors
http://www.linuxlinks.com/article/2016041003054574/TextEditors.html
Linux is blessed with a wealth of text editors to suit every person and editing need. Here's a list of some and a guide to choosing one that's right for both you and the task at hand.
#Linux #SysAdmin #Editors
http://www.linuxlinks.com/article/2016041003054574/TextEditors.html
Linux Tips & Tricks - Adding bookmarks to PDF files in Linux
Linux Tips & Tricks - Adding bookmarks to PDF files in Linux
While there are plenty of great tools to create, edit and modify PDF files in Linux, you might find these simple command line tricks quicker and easier.
#Linux #SysAdmin #PDF
http://ask.xmodulo.com/add-bookmarks-pdf-document-linux.html
While there are plenty of great tools to create, edit and modify PDF files in Linux, you might find these simple command line tricks quicker and easier.
#Linux #SysAdmin #PDF
http://ask.xmodulo.com/add-bookmarks-pdf-document-linux.html
Linux Tips & Tricks - Using "cat" and "tac"
Linux Tips & Tricks - Using "cat" and "tac"
More tools for your command line arsenal.
"cat" is one of those core command line tools you should learn to master. "tac" is a handy companion tool.
#Linux #SysAdmin #CommandLine
http://www.tecmint.com/learn-linux-cat-command-and-tac-command/
More tools for your command line arsenal.
"cat" is one of those core command line tools you should learn to master. "tac" is a handy companion tool.
#Linux #SysAdmin #CommandLine
http://www.tecmint.com/learn-linux-cat-command-and-tac-command/
Tuesday, 29 March 2016
Share file-systems the Unix/Linux way with NFS
Share file-systems the Unix/Linux way with NFS
I know a lot of people use other methods to share drives and folders between computers, including SMB (via SAMBA), but most often the right/best way is with the Network File System (NFS).
With NFS you can mount a drive or folder from your Linux server to a folder on your Linux PC (or other NFS supporting device). This makes for a seamless method of file sharing that also retains all the the native security and access control features of native Linux file systems. Like owner, group, and permissions information.
Take a look and learn NFS.
#Linux #UNIX #NFS #SysAdmin
http://ask.xmodulo.com/nfs-server-client-centos.html
I know a lot of people use other methods to share drives and folders between computers, including SMB (via SAMBA), but most often the right/best way is with the Network File System (NFS).
With NFS you can mount a drive or folder from your Linux server to a folder on your Linux PC (or other NFS supporting device). This makes for a seamless method of file sharing that also retains all the the native security and access control features of native Linux file systems. Like owner, group, and permissions information.
Take a look and learn NFS.
#Linux #UNIX #NFS #SysAdmin
http://ask.xmodulo.com/nfs-server-client-centos.html
Tuesday, 22 March 2016
Using the right software sources with OpenSUSE
Using the right software sources with OpenSUSE
OpenSUSE Linux has one of the largest software repositories in the Linux world. However, there will always be things you don't find right out of the box. Instead of rushing off and manually installing software, try doing it the right way first.
- First off, make sure it really isn't in the default repos. Often package names on SUSE are different than on Ubuntu, RedHat, Fedora, Debian etc. Instead of trying to install by package name, run YaST2 and use the excellent search capabilities of the package manager. Try disabling case sensitivity and enabling searching in descriptions and "provides". Then try variations on your search terms. Eg if you can't find UAE (the Amiga emulator) try searching for "Amiga".
- Next go to the package manager and see if there's a repository you need to add.
- If that fails, then search for the package in the OpenSUSE Build Service (OBS), at http://software.opensuse.org/search
#Linux #OpenSUSE #Sysadmin
OpenSUSE Linux has one of the largest software repositories in the Linux world. However, there will always be things you don't find right out of the box. Instead of rushing off and manually installing software, try doing it the right way first.
- First off, make sure it really isn't in the default repos. Often package names on SUSE are different than on Ubuntu, RedHat, Fedora, Debian etc. Instead of trying to install by package name, run YaST2 and use the excellent search capabilities of the package manager. Try disabling case sensitivity and enabling searching in descriptions and "provides". Then try variations on your search terms. Eg if you can't find UAE (the Amiga emulator) try searching for "Amiga".
- Next go to the package manager and see if there's a repository you need to add.
- If that fails, then search for the package in the OpenSUSE Build Service (OBS), at http://software.opensuse.org/search
#Linux #OpenSUSE #Sysadmin
Thursday, 10 March 2016
Linux - Upping your sysadmin game
Linux - Upping your sysadmin game
Here are 50 tutorials to help bring your Linux skills to the next level.
#Linux #Unix #MacOS #SysAdmin #Tutorials
http://www.thegeekstuff.com/2010/12/50-unix-linux-sysadmin-tutorials/
Here are 50 tutorials to help bring your Linux skills to the next level.
#Linux #Unix #MacOS #SysAdmin #Tutorials
http://www.thegeekstuff.com/2010/12/50-unix-linux-sysadmin-tutorials/
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