Archivio tag: troubleshooting

Bookmarks for 2 ott 2014 through 3 ott 2014

These are my links for 2 ott 2014 through 3 ott 2014:

Bookmarks for 25 set 2014 from 12:03 to 17:40

These are my links for 25 set 2014 from 12:03 to 17:40:

  • sebsauvage/rss-bridge – The RSS feed for websites missing it
  • debsecan – The debsecan program evaluates the security status of a host running the Debian operation system. It reports missing security updates and known vulnerabilities in the programs which are installed on the host. debsecan accesses the dpkg database and obtains a list of installed packages and their versions. This list is then evaluated against a feed of vulnerability information which ultimately comes from a database maintained by Debian's Testing Security Team . Various output formats are supported, including incremental reporting via email. Beginning with version 0.2, debsecan includes a script called debsecan-create-cron, which allows you to create a cron job which periodically sends you mail (once per day) when the security status of the system changes.
  • Barriers, Caches, Filesystems | monolight – With the recent proliferation of ext4 as the new “default” Linux filesystem there’s been much talk of write barrier support. The flurry of post-2.6.18 barrier related development in most storage subsystems has left some novice users and administrators perplexed. I hope I can clear it up a bit with this primer/refresher.
  • SMTP, testing via Telnet – FreeBSDwiki – When troubleshooting problems with SMTP service – your own, or others – it is frequently very helpful to be able to "speak" to the SMTP server directly, rather than going through a mail client which won't necessarily tell you exactly what the SMTP server is saying. You can easily do this with the telnet client. Note that many ISPs do not allow outbound connections on port 25 to any SMTP server but their own – if you get timeouts when trying to connect to port 25, you should try port 587, which is the standard ESMTP port. (Port 587 connections normally require SMTP AUTH, which is covered below.)

Bookmarks for 26 ago 2014 through 27 ago 2014

These are my links for 26 ago 2014 through 27 ago 2014:

  • Regular Expressions – Regular expressions ("regexes") are supercharged Find/Replace string operations. Regular expressions are used when editing text in a text editor, to: check whether the text contains a certain pattern find those pattern matches, if there are any pull information (i.e. substrings) out of the text make modifications to the text. As well as text editors, almost every high-level programming language includes support for regular expressions. In this context "the text" is just a string variable, but the operations available are the same. Some programming languages (Perl, JavaScript) even provide dedicated syntax for regular expression operations.
  • MySQL active-passive cluster | Your IT goes Linux – We will use the iSCSI Lun defined in our iSCSI cluster as a shared storage and we will run MySQL in active-passive (fail-over) mode using Pacemaker and Corosync cluster engine. The cluster will have to connect to the iSCSI target, mount the iSCSI partition on one node and start a MySQL service which has all its data on this partition.
  • Perl – [...] Perl has horrors, but it also has some great redeeming features. In this respect it is like every other programming language ever created. This document is intended to be informative, not evangelical. It is aimed at people who, like me: dislike the official Perl documentation at http://perl.org/ for being intensely technical and giving far too much space to very unusual edge cases learn new programming languages most quickly by "axiom and example" wish Larry Wall would get to the point already know how to program in general terms don't care about Perl beyond what's necessary to get the job done. This document is intended to be as short as possible, but no shorter[...]
  • Linux Performance – This page links to various Linux performance material I've created, including the tools maps on the right, which show: Linux observability tools, Linux benchmarking tools, Linux tuning tools, and Linux observability sar. For more diagrams, see my slide decks below.
  • AIXchange: Useful Storage Links – Here's an assortment of really good storage-related articles — the majority of which are found on IBM developerWorks — that are worth your time. While some of them are a few years old, they still provide relevant information.

Bookmarks for 30 apr 2014 through 6 mag 2014

These are my links for 30 apr 2014 through 6 mag 2014:

  • Ralentir le débit de postfix pour wanadoo/orange – Le blog de Michauko – Si vous avez un serveur d’envoi de mails (je ne parle pas d’être un spammeur) et beaucoup d’abonnés chez Wanadoo et Orange, vous risquez fort le rejet temporaire de votre serveur si le débit d’envoi est trop fort. C’est ce qui m’est arrivé et hop, 5000 mails entassés dans la file de postfix.
  • smtp-in.orange.fr refused to talk to me: postfix solution | floriancrouzat.net – Orange sadly limits inbound connexion to it’s MX to 1 connexion per IP, which is a total pain in the ass when you try to deliver newsletter, or manage a MTA. Here is a sample log from their MX: Jul 4 10:42:42 smtp.example.com postfix/smtp[32347]: 0123456789: host smtp-in.orange.fr[193.252.22.65] refused to talk to me: 421 mwinf5c34 ME Trop de connexions, veuillez verifier votre configuration. Too many connections, slow down. OFR004_104 [104] However, since they won’t change anything, we have to take mesures, here’s what you can do if you run postfix: you have to set a per-destination concurrency limit.
  • Aral Balkan: Historical Archive — How to revert (roll back) to a previous revision with Subversion – Here, then, is a very simple, plain English explanation of how to revert to a previous version of your application in Subversion, to help anyone who may be starting out with it and is lost.
  • Tmux: A Simple Start – In all likelihood, you’ve probably already heard of tmux. However, you may not be using it everyday. If tmux is on your “Someday” list because you think it is too complicated (I mean, c’mon, the word “multiplexer” is just plain scary), then I am here to show you just how easy it is to put tmux into your workflow.
  • Tyblog | Yet Another Vim Setup – Vim is an excellent text editor. I’ve used it for many years and like most vim users, have collected a fairly large collection of settings in my .vimrc and learned how to grok my vim usage effectively through a lot of trial and error. To that end, I’ve tried to assemble a useful overview of my experience with vim.