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Systemd

[Now updated for 2015!] Component Status systemd Replaces init, cron, inetd, udev, locale, acpid, atd, su. systemd-journald Replaces syslog, klog. systemd-logind Replaces getty, login, xdm. (*) systemd-networkd Replaces ifup, ifdown, tcpwrapper, hostname, dhcpd. systemd-journal-gatewayd Provides HTTP server for systemd-journal. systemd-timesync Replaces NTP. systemd-resolved Replaces resolvconf, bind, powerdns-recursor, dnsmasq. systemd-automount Replaces autofs.…

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Playing Domino without a POODLE

If you run any kind of Internet server, you’ve hopefully heard about the POODLE vulnerability in SSL 3. If you run a Domino server, you need to worry about this, because Firefox plan to turn off SSLv3 support in their next release in a couple of weeks and remove the code in the release after that — and Chrome will follow soon after. SSLv3 is the only secure connection supported in Domino out of the box, so that could leave you with no HTTPS support.…

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In the wake of shellshock

So, shellshock. It’s big. I think it’s bigger than heartbleed, because the bug has been in the code for 22 years, so there are an awful lot of systems out there with a vulnerable shell installed and nobody maintaining them properly. One misconception I’ve seen posted across the web is that you’re not in trouble if you don’t use bash as your shell, or that you’re safe if you have dash as /bin/sh.…

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Setting up DB2 on Linux

This is a quick sketch of the typical process for setting up individual user IDs to access a DB2 database on a Linux-based DB2 server — basically, the bare essential things to do which aren’t covered by the DB2 installation guide. Before attempting the DB2 install, install the necessary additional packages:

apt-get install libxrender1 libxft2 libxtst6 libxi6 libaio1 ksh libstdc++6-4.4-dev libstdc++6-4.4-pic libstdc++5 rpm Install DB2, and check licensing is set up correctly via db2licm -l.

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DB2 10.1 db2fmcd general protection fault

The problem: You want DB2 to start up automatically at boot, so you use the official method and enable the fault monitoring system and then use db2iauto -on instancename to enable autostart. On rebooting, DB2 isn’t started. You check /var/log/syslog and see: Jun 13 15:37:05 servername kernel: [ 67.324105] db2fmcd[1357] general protection ip:7fa9c68306c4 sp:7fff86c43150 error:0 in libc-2.15.so[7fa9c67c2000+1b5000] or something similar. Yes, ironically enough, the fault monitor has caused a general protection fault.…

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Jay: A program for removing excess kernels

Ubuntu is pretty easy as far as regular software maintenance goes, thanks to APT. However, there’s one task which (as far as I can tell) isn’t automated. Whenever there’s a minor update to the Linux kernel, apt-get (or GUI equivalent) will diligently download and install it. Unlike with applications, though, APT doesn’t remove the old version — because you’re running it, and bad things can happen if dynamically loadable kernel modules disappear while the system is running.…

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Adjusting ulimit -n

The first time you run IBM Lotus Domino server on a new Red Hat Enterprise Linux (RHEL) box, you get the following message: WARNING: the maximum number of file handles (ulimit -n) allowed for Domino is 1024. See Release Notes and set the allowable maximum to 20000. This message is less than ideal for a couple of reasons. Firstly, it doesn’t tell you how you’re supposed to change ulimit, and secondly it hints at the wrong way of doing it.…

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RPM cheat sheet

The worst thing about commercial Linux is RPM. I can never remember the command line incantations required for even fairly simple tasks. While yum eventually takes away the pain of applying software updates — so long as you’re not in a hurry — there are all kinds of other tasks it doesn’t handle. I therefore rely on an RPM cheat sheet I’ve assembled over the years. Here’s a copy for anyone else who might find it useful.…

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inode diet

I keep all my music on a server in the corner of my office, so it’s accessible from any machine in the house. I recently rebuilt the OS install on the machine (Linux, of course), and reformatted the hard drives to get rid of ReiserFS and switch to ext3. After putting back all the data to a single temporary partition, I took a look at my inode usage. df -i reported that the main data partition had 101875 inodes used out of 9281536, and df –si reported 135G used.…

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