Autarchy of the Private Cave

Tiny bits of bioinformatics, [web-]programming etc

    Linux server remote backup options

    3rd October 2010

    Recently I finally managed to configure remote (aka off-site) backup for my Debian server. As always, I started with a comparison of existing solutions.

    Debian has a number of packages enabling remote (over the network) backup: backupPC, backupninja, backup-manager, dirvish, duplicity, luckybackup, rdiff-backup, and some others.

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    Posted in *nix, Links, Software | 1 Comment »

    Does Google attack your servers, too?

    5th December 2009

    Evil?

    For about 2 weeks now, I am every day alerted of the suspicious behavior of some computer/server from the Google’s IP range:
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    Posted in Misc, Web | No Comments »

    Which Hosting Control Panel to use for a Debian server?

    27th September 2008

    To cut the long story short: for the final evaluation, I had this line of control panels:

    SysCP: looks good to me (though demo isn’t functional), has customer billing module. Unsure as to where it is used, but most probably sponsors are also the users of SysCP. Majority of support forums are in German.

    DTC: has no demo, only some screenshots. Has a set of packages for Debian lenny (which is a huge plus for maintenance and future upgrades). DTC is being developed by GPLHost, and is also used by GPLHost – so this is a live (used) distribution. Seems quite feature-rich.

    Virtualmin claims to be the “world’s most powerful and flexible web server control panel”. Virtualmin offers 4 means to control it: Web, mobile device, command line, and remote API. There are both screenshots and demo. Has both GPL and Professional versions. GPL version has a number of limitations, comparing to Pro version. From what I’ve read about Webmin (all three – Virtualmin, Webmin, Usermin – are just different “layers” of server control), it is a framework with a number of “interface scripts”, which allow to control various services. As such, it is easily extendible, but is not monolithic – in the sense of module inter-dependencies and action triggers.

    RavenCore was a promising CP.

    GNUPanel is a year-old control panel, but has a news item on the front page (dated August, 17) promising new, completely rewritten release somewhere in October. By the feature list, looks promising. However, I need the panel right now, and even in October, that will be quite a rough release, not really used/tested anywhere, so not a good option as well. But GNUPanel is a panel to check in half a year for progress.

    As the final choice, I had ISPConfig (which seems to be the best by people’s comments), and which is also quite widely used, and is easy to install onto Debian (at least the Perfect setup: Debian Etch says so), and DTC. I discarded Virtualmin (for the poor functionality of the GPLed version), RavenCore (for the lack of current descriptions and non-functioning demo), GNUPanel (which just isn’t ready yet), and SysCP (because ISPConfig seems better ;) ).

    As DTC has Debian packages (and will be easier to maintain/upgrade), I decided to try it first. I already have it installed (that’s easy, esp. if you first read the DTC Debian Express Setup). Later I might post my impressions from using DTC.

    Update: DTC is indeed easy and pleasant to use. I had problems allowing FTP and SSH access using MySQL authorization, but at least FTP was an easy one to fix (SSH access with MySQL authorization is still unconfigured, but that’s a low priority for me). There is a minor concern about the files and directory permissions setup, but thanks to chrooted environment that is only minor concern. Use of a single Apache installation for hosting admin and serving user sites might be a sub-optimal decision, but it works. Traffic and disk space accounting are plain superb! Server memory use for the dtc-toaster installation is troublesome, but for a powerful RAM-my server that is not a problem (I now have about 800-900MiB RAM occupied, but that includes the XCache’s cache, quite big MySQL cache, and loads of Apache and PHP modules).

    But I’m still willing to try other control panels. As I expected, GNUPanel hasn’t released anything yet; Ravencore‘s online demo is still unfunctional; ISPConfig has recently released RC (and their demo is working as it should and as it used to); SysCP is also up and running fast. If my little hosting service starts pouring in some cash, then I’ll try SysCP on my second server – to compare it with DTC, and choose one of them for further support/extension/localization.

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    Posted in *nix, Notepad, Software, Web | 17 Comments »

    Need a computer science paper? Try SCIgen!

    9th December 2007

    Quite an entertaining story:
    SCIgen at wikipedia
    SCIgen tool
    SCIgen blog

    Finally, just a useful resource if you need a shiny name for your brand-new 2.0-beta project: anagram server.

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    Posted in Humour, Links, Science | 1 Comment »

    Ukrainian web-portal bigmir.net switched from own free email service to gmail

    30th October 2007

    Just a minute ago, I was shocked after logging in to mail.bigmir.net: instead of the bigmir’s own, HTML-only email interface, I got redirected at the gmail’s “Terms and conditions”, after accepting which I found my emails in the classic gmail mailbox.

    First thing to think about: at least they did transfer all my emails to the new account.

    Second: hey, they had given up their own email interface! Are they leaving the web-portal market of Ukraine? Was the part of their team (which later formed MI6) too important to handle their exodus with no consequences? Is that just a desire to give customers “better” interface and not invest anything into development?

    I hope this won’t be a trend, for every service to have Google behind their servers. Or even just behind the name, to avoid extra complexity of having a server.

    Finally, I think I’ll get used. But it was only yesterday, that I read the Google anti-utopia, where Big Brother’s name is (evidently) Google, and it’s webcams and microphones and search history define each person’s future AND guilt. Scary…

    And I wonder which will be the next service of bigmir.net, “outsourced” like their email.

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    Posted in Misc, Web | No Comments »

    GoDaddy: undocumented 20-second CPU time maximal execution limit? (python, ELF, etc)

    16th October 2007

    Today, setting up a relatively serious (in CPU resources needed) web-system, I ran into a weird problem of python scripts ending prematurely. After some investigation, it looked like any process which uses up more than 20 seconds of CPU time, is automatically killed. To verify this, I wrote an infinite loop in C,

    int main () {
    unsigned int i;

    for (i = 0; i < 2 ; i++ ) { i = 0; } return 0; } [/c] compiled it and executed several times on the GoDaddy shared hosting server. I did observe the program running for the maximum of 20 seconds of CPU time, not a second more. Please note, that 20 seconds of CPU time can be much more of “real” time, if the script isn’t using 100% of CPU, which often the case for shared hosting. Thus if you have in your php.ini max_execution_time set to, say, 60 seconds, your php script may actually execute as long as one minute; but I’m pretty sure that if your script has lots of CPU-intensive procedures, then as soon as it uses 20 seconds of CPU time, it will be terminated (however, this statement still needs checking – anyone?). To verify, I also created a cron job with the same file. It ran for 30 seconds CPU time. Strangely, this behaviour is not documented anywhere. This limit may also explain a number of other problems, if you have heavy web-applications: they just might be killed before they are finished, causing errors. I do understand the reason for this limitation, and am sure similar limitations exist in other shared hosting environments. The only important thing here is that this limit should have been documented and even put upfront somewhere in the hosting plans descriptions. I also wonder if the limit is the same for all godaddy shared hosting plans, or if it differs. 20 seconds when executed from PHP, and 30 seconds when executed as a cron job were observed on the Deluxe Linux Hosting plan. Extensions, additions and comments are welcome.

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    Posted in *nix, Misc, Programming, Web | 22 Comments »