Articles in the Uncategorized category

  1. Why VMware vSphere Replication Is Changing the Game

    Mon 12 November 2012

    If you are running a serious VMware environment, chances are you do have a SAN. Often with smaller setups, many people do employ multiple VMware hosts, but the SAN is a single point of failure.

    SANs are often fully redundant devices, with redundant PSUs, storage controllers, network links and RAID arrays. But with all that redundancy build in, they still fail. I've seen it happen and a failing SAN is the worst.

    So I'd rather have two cheap entry level SANs if possible than just a single big one and keeping my fingers crossed that they won't fail.

    A redundant SAN environment where you basically deploy two separate SAN devices with their own storage needs a replication setup. And replication between SAN environments needs often extra licences or more expensive setups. And the replication mechanism must play well with your virtualisation layer, such as VMware.

    But the fun thing is that VMware made everything way simpler by integrating their own storage replication into their vSphere product. I have no experience whatsoever with VMware's new build-in replication feature. But I believe that it is significant.

    Replication is a new feature introduced in VMware vSphere 5.1 that is now part of the vSphere Essentials Plus Kit and vSphere Standard. So if you start with two or three VMware hosts and two entry-level SAN devices, you can be quite redundant and can have a fully redundant setup. And that will cost you around 3800 Euro ~ 4800 US dollar.

    The Essentials Plus Kit is a nice environment for smaller companies, but license-wise, it does not scale as you are stuck with a maximum of 6 physical CPUs and a maximum of three hosts. However it seems that when you need to expand beyond that capacity, you can trade in your existing license and obtain a discount when upgrading to - for example - vSphere Standard or Enterprise.

    The most significant thing about the build-in replication is that it does not matter any more what you use for your storage backend. If you use two entirely different devices from different vendors, that's OK. Because VMware handles all the replication stuff. Those SAN devices become just dumb storage boxes. Most of us just can configure whatever does support iSCSI.

    You could even try and be cheap and setup your own homegrown storage boxes. It may not have all the cool features of a true SAN, but at least you have redundant storage.

    I'm really curious about this feature and I hope it works well. I'm seriously considering deploying this for the VMware setup of the company I currently work for. It does however require an extra external host that manages the actual replication, which may add to the cost.

    Any comments are welcome.

  2. Why I Bought a Digital Projector (Panasonic PT-AT5000E)

    Sun 21 October 2012

    I don't have a TV. I haven't been watching TV for more than 10 years. But I love to watch movies or great series like Dexter and Game of Thrones. Until recently, I watched movies or series on my 27" iMac. Twenty-seven inch is large for a computer screen but for a TV, it's quite small.

    home setup

    When it comes to watching movies, a bigger screen is always better. The big screen of a movie theater is the most important reason for movie enthousiasts to experience a movie in the theatre. But there is a way to get that movie theatre feel into your living room: get a digital projector. That's what I did.

    I decided to get a ceiling mounted projection screen that I could lower just in front of my computer and table. I chose the "celexon Rollo Economy with a dimension of 277 x 156 cm (109 x 61 inch). This would give me a TV screen with a theoretical size of 125 inch in diameter! In practice, the actual projected image is around 120 inch.

    Just think about that. A 120 inch television. Hundred-and-twenty inch. Three metres diagonal.

    screen retracted

    The screen can be lowered by just pulling on the edge. I have to reach for it on my toes but it's ok. As pictured below, the screen has an additional black area so it can be lowered further away from the ceiling. This way, the effect of the ceiling reflecting light back to the screen, reducing picture quality, is reduced. It allows you to have the screen at the desired hight, you don't need to look up.

    screen retracted

    At the other end of the room, I decided to mount a projector on a ceiling mount. My iMac would sent all digital content through a long HDMI cable to the projector.

    After doing some research I decided to buy the Panasonic PT-AT5000E also known as the PT-AE7000. This digital projector supports Full HD 1080p at 1920x1080. It also supports 3D but I'm not really interested in that.

    projector

    I have never seen a movie on a digital projector before and I can't compare it to other digital projectors. But one thing is sure. Watching a 1080p movie on a 120" display projected by this digital projector is quite an experience. To me the picture is astounding. It is almost if you are in a theatre. A digital projector may not always be practical, but it is surely awesome.

    I do have some remarks about the whole setup with a digital projector:

    1. you need a big screen and mount it somewhere;
    2. the projector is just gigantic and you must accept that it hangs from your ceiling somewhere, something your spouse may not like;
    3. you need to run some extra cables for power and HDMI through your house;
    4. you need to put the lens cap on when the device is not in use, often a hassle;
    5. the lamp takes several minutes to reach optimal operational temperature;
    6. although my panasonic projector is almost silent, it does make noise;
    7. you must have good curtains to block all external light or you won't see a thing;
    8. you need to wait for movies to be released on Blu-ray or the Internet to be able to watch them;
    9. the lamp will wear out and replacements are expensive;
    10. if anyone would ask you about the size of your TV you would have to lie or feel a douchebag for telling the truth.
    11. Non-HD content looks totally crap and you need to make the picture smaller just to stand it.
    12. the whole home theatre setup is just expensive and you could have bought a lot of theatre tickets for that money;
    13. black levels are often not as good as plasma TV's.

    But in the end I would not hesitate to fork out the money for a home theatre setup like this. Because of the downside of movie theatres:

    1. other people. They are the cause that you don't have the best seat in front of the screen;
    2. more other people, who text, talk or phone during the movie;
    3. even more other people, who eat crappy food, making noise and drink crappy liquids as if it where a slurping contest;
    4. you need to pay money;
    5. you need to sit in some crappy movie theatre chair;
    6. you must pay top dollar for a drink or food;
    7. no pauses so no toilet breaks;
    8. you need to go there, and be there at a specific time;
    9. you need to stand many commercials before the movie actually starts;
    10. the sound quality is often horrible.

    So in my opinion, if you you are willing to spend money on it, I would advice to seriously look into getting a digital projector.

  3. Compiling Multicore PAR2 on Ubuntu 12.04 LTS Precise Pangolin

    Sun 16 September 2012

    If you want to compile PAR2 with multicore support on Linux, it may not work right away from source. I used this version of PAR2 with multicore support. Update 2015: the original link is dead, I foud a copy of the source and put it on my own site here for you to download.

    First, make sure that you have these libraries on your system:

    libtbb-dev
    libaio-dev
    

    According to this source, after downloading the source, you need to add this line:

    #include <backward/auto_ptr.h>
    

    To these files:

    par2cmdline.cpp
    commandline.cpp
    par2creator.cpp
    par2repairer.cpp
    

    Then edit the Makefile and find the LDADD variable. Add the -lrt option like this:

    LDADD = -lstdc++ -ltbb -lrt -L.
    

    This did the trick for me and compiled the PAR2 source with multicore support. Hope it helps somebody.

    If you want to use Multicore PAR2 with SABNZBD you need to go to the Config menu. Then select 'Special' and enable 'par2_multicore'. Save the changes. Then go to 'Switches' and enter '-t+' at the Extra PAR2 Parameters field.

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