Some irritation due to extended output of systemd / systemctl status for sysv services


Bad is an unpleasant word, right? “On” or “off” implies some final statement, or “failed” may signal something wrong but at least terminated. But “bad”… uuuhh, blameworthy, guilty, unaccountable, still being around. Ok, before diving into linguistic depression, the change eventually turned out simple and was actually in good faith but, however, produced remarkable irritation. You know, systemctl status {service} will show an overview of some systemd unit definition with load state, current activity and so on. The load state, in particular, details, in parantheses, into the path of the unit file, the enablement and the vendor enablement preset, respectively. Original systemd units may give a load state as follows:

Loaded: loaded (/usr/lib/systemd/system/atop.service; enabled; vendor preset: disabled)

However, systemd units, that have just been derived from systemv init scripts, only printed the init script path since lately:

Loaded: loaded (/etc/rc.d/init.d/sysv-thing)

The new irritating factor now is an extension for those derived systemv init scripts, to also state the enablement, but show up as “bad” for the running enablement for whatever weird reason:

Loaded: loaded (/etc/rc.d/init.d/sysv-thing; bad; vendor preset: disabled)

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Scheduling / descheduling linux host reboots via shutdown


Scheduling and/or descheduling linux host reboots is possible with the shutdown -r command using the time parameter (the reboot command, that I usually prefer in favour of clarity, does’nt feature the time parameter, so shutdown -r is the only choice here). Aside from discussing the quite straightforward man page of shutdown, there is two points here to register in your knowledge cells.
First, a (scheduled) shutdown -r hh24:mi execution will hangup itself into background, no need to use job-tools or an &. shutdown -r hh24:mi actually puts systemd-shutdownd in charge of serving the party, this is what you”ll want to expect to see in your running process list, looking for some command effect. Also, a running scheduled shutdown may be cancelled using shutdown -c any time before hh24:mi. Note however, that from around five minutes before hh24:mi, you’ll you’ll no longer be allowed to login the machine, essentially impeding any further control from your side.

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Understanding “occurrences before alerts” in oracle enterprise manager 13c


The Incident Manager within Oracle Enterprise Manager 13c is a powerful tool for monitoring a wealth of target types such as databases, hosts, middleware or just services in general from a bird’s eye view or right down into the manifold details of a dedicated application. As with all powerful means around, where there is a lot of power, there also usually is a lot to do wrong (or even employ counterproductive). This is why it is important to understand the Incident Manager concepts from bottom up and be able to identify the knobs and wheels to poke with to meet a certain requirement.

Basically, Incident Manager is a professional toolset to facilitate the management of non-critical and critical system alerts against metric values (registered as problems and incidents, see About Incidents and Problems) in a larger quantity and time scale along with alert management templating and alert assigment and so forth.

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Splitting a btrfs 4.1x root partition with debian live system gparted btrfs tools 3.17-x


This is a short picture log of doing a btrfs 4.1x root partition split on a (down) oracle linux 7.2 using a debian live system applying gparted based on btrfs tools 3.17-x. Lot’s of names and version codecs, right? But this is what matters. The important message is : it works using this flavours.
Actually, running oracle or redhat linux as the live system may have been much more appropriate concerning compatibility reasons. The odd things is, no redhat-based (enterprise) linux system features gparted. Only fedora does, sourcing the epel-repository but not having kinf of a live system release as debian.

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The look of : transaction deadlock due to missing foreign key index


This about transaction deadlocks resulting from an index missing on foreign key colum(s). Actually, the post will not dive into the odds resulting from this failure but show how to detect this dedicated reason for an “ORA-00060: deadlock detected while waiting for resource” message. In particular, what to look out for in the trace file and how to find the table objects (instead of rows) being deadlocked against each other. The best resource on the web tackling this subject is of course (Reading deadlock trace files) from Tom Kyte, which also guided me along the way of a “no row deadlock”, see below.
Ok, on first place, some tool, Enterprise Manager for example, or whatever will notify you about entries in the alert.log, reading roughly the like as “Sun May 29 02:51:07 2016 ORA-00060: Deadlock detected. More info in file H:\ORACLE\diag\rdbms\got\got\trace\got_ora_4536.trc“. Inspecting the trace file, you should focus your attention on the first 70 lines, in most cases neglegting the trailing process information dumps. I got this, anything noteworthy will be highlighted and discussed below:

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