Also available to us is ZFS compression. Let’s create a test pool for testing. We’ll turn a few options on and off so you see the syntax:
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# zfs create -o mountpoint=/compressfs -o dedup=off \ > -o compression=on datapool/compressfs |
Note: This article was written alongside BIND 10 1.0.0-beta. See this article which covers the major differences to be aware of between 1.0.0-beta, and 1.0.0-rc.
I’ve been an avid BIND 9 administrator for many years, and have found its configuration to be straightforward and the software itself to be reliable and RFC compliant wherever I’ve taken the time to check RFC compliance. My only criticism of BIND 9 was not being able to easily and instantly provision new zones (e.g. requiring an rndc reconfig to add new zones), without the use of DLZ (Dynamically Loadable Zones). DLZ (http://bind-dlz.sourceforge.
BIND 10 will replace BIND 9 and ISC DHCP, and thus BIND 10 comprises processes to handle both authoritative and recursive DNS, as well as DHCPv4 and DHCPv6.
BIND 10 is still in development, and this article has been written around the current release (BIND 10 1.0.0 beta). SQLite is the only supported backend at present (except for DHCPv6 which confusingly supports only MySQL).
I’m sure ISC will release a coherent product as development continues, but in my opinion they have released a confusing and very incomplete beta version of BIND 10. The BIND 10 Guide (http://bind10.isc.org/docs/
I will do my best to give BIND 9 admins an interesting overview of getting BIND 10 up and running on a fresh CentOS install, and will demonstrate some of the features available, basic configuration, architecture of the new software and so on.
Stand by guys – it’s going to be odd. Very odd. I’ll be posting new articles as I learn more about BIND 10, so what you read in this article may be superseded by a later article (once I find a better/correct way of doing something, or BIND 10 itself changes).
Telecommuting is supposed to be everywhere: it’s the dawn of a new age, where almost everyone works from home, reducing costs to employers and skyrocketing productivity. But is this actually the case? And where are all these work-for-your-company-from-home-ers, not self-employed yet still enjoying the flexibility and freedom that telecommuting permits?
I’ve worked for several large companies over the years, enjoying the benefits that the corporate environment provides, but I’ve never found an environment better than that provided by telecommuting. Interestingly, however, my only experience with permanent telecommuting was in the last 6 months of my previous job, when my wife was severely ill and I had to stay home to look after her while also working full-time. My boss commented that I was as productive as ever, and the fact that I often worked sporadic hours, sometimes through the night, had no effect on the running of the business - my work was being done when it needed to be done (as we provided support across several timezones), I was involved in conference calls and I could still talk directly with others I was working with via IM or the phone.
When using Postfix, the following simple one liner will do the trick to remove bounces:
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# mailq | grep MAILER-DAEMON | awk '{print $1}' | sed 's/\*//' | postsuper -d - |
OK – we’re good to go for our final ZFS configuration. Recall from earlier that I will be configuring a two-disk RAID1 set, with an extra disk for hot-spare use, and the final disk to play with for backups, encryption, dedup, etc.
I wanted to remove a large number of files from a directory. However, I did not want to descend into subdirectories, nor did I want to remove any .pdf or .chm files. Some of the files had non-standard characters (such as quotes and spaces) in them.
The solution? A simple one liner using find and xargs:
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$ find . \( ! -name "*.pdf" -a ! -name "*.chm" \) -maxdepth 1 -type f -print0 | xargs -0 rm |
Within Apache HTTPD’s mod_rewrite, RewriteCond only applies one RewriteRule that comes immediately after the RewriteCond itself. It didn’t seem like such a great idea to have to duplicate a lengthy RewriteCond definition half a dozen times for multiple RewriteRules.
Turns out there is a fairly simple trick to achieve exactly what I was looking for: if the RewriteCond is negated and followed by RewriteRule . – [S=n] to skip the following n rules, the RewriteRules in essence are only applied when the singular RewriteCond is true. Like so:
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RewriteCond %{REQUEST_URI} !^/(pattern1|pattern2|pattern3)/$ [NC] RewriteRule . - [S=3] RewriteRule ^/pattern1/$ /someURL.php [L] RewriteRule ^/pattern2/$ /someURL2.php [L] RewriteRule ^/pattern3/$ /iLikeDoughnuts.php [L] |
Now the last three rules are skipped if the condition is not true or, in reverse, they are applied if the condition is true. Each pattern is then handled individually, and the [L] rewrite option will cause only the pertinent rule to be applied - processing will stop after the first matched condition.
ZFS is simply awesome. It simplifies storage management, performs well, is fault-tolerant and scalable and generally is just amazing. I will use this article to demonstrate some of its interesting features. Note that we are only scraping the tip of the ZFS iceberg here; read the official documentation for much more detail. The terms dataset and filesystem are used interchangeably throughout as with ZFS they are essentially the same thing.
The aim of this series is to show the experienced Solaris system administrator how to transition from Solaris 10 to Solaris 11 immediately after initial installation of the operating system, as well as offering tips, tricks and insights into Solaris 11, which differs significantly from Solaris 10.
This article will cover the commands that will enable both servers to be networked and able to reach the internet.
As a System Administrator, there are many things that you need to know; you can’t just point and click your way around problems. While the number of skills is vast, I’ve narrowed them down to my list of the top 5 practices of a good UNIX System Administrator.