Linux thoughts from a linux Geek (aka GEEX)

I just copied this post from http://taksuyama.com, I use it for my personal reference. - Because it matters – http://taksuyama.com - BackupPC SetUp: with rsyncd on Windows XP without Cygwin

Linux is not Windows XP and if reboot fail you usually still connect by SSH and do something. This commands will show you how to remotely hard reboot machine. Hard reboot mean that shutdown scripts will not run and machine reboot immediately without syncing hard disk drives, shutdown applications etc, it’s more like hitting the reset button.

Here I come again with a tiny command line that can speed up the usual method of copying large amounts of data. Sometime ago a college gave me a DVD that I would like to keep to myself but that other 2 colleges wanted too. I used dd, cat and ssh for the task. Taking less that 5 minutes to do it all.

SSH is extremely versatile and although the use of tunnels is a well know feature of ssh the reverse tunnel is not. First where can you use a reverse tunnel? Imagine that you need to service a server/desktop that is behind a firewall and the only communication available is must be started on the host behind the firewall.

Today I was working on something and had to check something related to the IP protocol so I went to the Wikipedia page. On the main page usually there is a chart and a message asking people to contribute so wikipedia can continue to be free, in the matter free as free of adds…

Lots of people ask me what’s the best Linux distro, some say what’s the best for a newbie others want to setup a home server and some others want to build a gatekeeper. So what’s the best distro to accomplish all this?

This version adds USB 3.0 support, a equivalent of FUSE for character devices used for proxying OSS sound to ALSA, some memory management changes that improve interactivity in desktops, readahead improvements, ATI Radeon Modesetting support, support for Intel’s Wireless Multicomm 3200 Wifi devices, kernel support and a userspace tool for performance counters, gcov support…

Last time I wrote about the Hobao Hyper 9  I was waiting the 9.5 arrival. It did arrived and I managed to put a gallon on it on practice plus a weekend competition. The competition didn’t go that well but it wasn’t the cars fault, just did practice and qualifications having to leave afterwards. But lets go to what matters, how’s the Hyper 9.5 GL behaving and what are the new features? Hyper 9.5 GL has some big improvements on its predecessor the Hyper 9 here’s a list:

1. 4mm thick + 4mm longer rear lightweight chassis
2. CNC Front chassis brace
3. CNC Rear chassis brace
4. Spider diff (front 5000, center 3000, rear 1000)
5. 20 Degree engine mount
6. CNC Coordinator mount
7. 17mm (20mm) Big Bore shock set
8. White spring set
9. CNC one piece shock top cap set
10. Fiber brake disc set up
11. Front +2mm wheel hubs
12. Rear +4mm wheel hubs
13. Rear 3mm stabilizer
14. Dust proof wheel nuts
15. Proline 9024 tires

In my opinion on this list of upgrades from the hyper 9 to the 9.5 the really important ones are:

1. 4mm thick + 4mm longer rear lightweight chassis
2. CNC Front chassis brace
3. CNC Rear chassis brace
4. 17mm (20mm) Big Bore shock set
5. White spring set
6. Dust proof wheel nuts

With the new chassis and braces I’ve been damaging lot less parts than I had with the Hyper 9, specially the center dogbones and plastics, the new shocks are also great in handling as the new springs. The dust proof wheel nuts aren’t just a fancy upgrade they do help a lot preventing dust inside the nuts making it faster to replace or upgrade parts on the track. About all the other improvements they work really well the brakes are much better, tiny springs where added to the brake pads this makes the brake free as soon as you hit the accelerator. The differential as better too, although I didn’t complain on the previous ones. What I didn’t enjoy that much and reverted to the setting of the hyper 9 was the engine mount, I like the 25 degrees engine mount better, in my opinion the car handles better, but maybe it’s just me that I’m used to the older mount. About the handling, what can I say, I loved the car before can’t deny it, but now I love it even more (my wife will kill me for saying this) but the handling in curve is better with the new chassis, the life cycle of parts is improved, I ran the gallon and the track weekend with almost no maintaince other than changing shock springs for tunning, and some minor setups (specially on the brakes). I’ve also noticed that with the with the white springs I can go faster on the corners without rolling. I also enjoy the gray ones for tracks that doesn’t have that many jumps. What more can I say about the car, not much, just a little comparison I’ve been driving an HotBodies D8 and a Kyosho MP9 and compared to the D8 I like the Hyper 9 much more but compared to the Kyosho… well the Kyosho is a really nice car too, it’s fast and small like the Hyper, they both fly well and turn well in the long run I think the Hyper may have some advantage in what matters to shocks and turning speed, in accelaration they both perform very well but i think with the kyosho you can accelerate a bit sooner existing the corners, but this is just a thought, didn’t do an extensive test. I’m more experienced with the hyper and it shows on lap times, but with the Kyosho I’m a second and a half slower, maybe due to the lack of habit driving it, with the D8 well… I’m three and a half seconds slower…and I’m equally used to it as I am with the Kyosho MP9. In conclusion I think the Hyper 9.5 GL a great evolution on the hyper, it’s not that cheap nor it’s a car free of trouble, but is one of the best RC cars out there at least that I’ve drove, on the bottom end I really dislike the access to electronics as you have to take out the break linkage to change battery or do something else in the box, but well perfection doesn’t exist ;) Cheers, Pedro Oliveira

As a part of my work I have to design and plan Hardware, Systems and Software deployment, and as many of you guys know sometimes it’s not that easy. Dimensioning hardware for specific roles can be a pain, sometimes you don’t even have the software as it’s being “produced” by the development team and still you have to tell how many machines, routers, switches and all the small things the project will take. But some other projects aren’t this difficult and you don’t need such an amount of flexibility to do them, you don’t need a custom based firewall cluster, you don’t need a web server or database cluster, you just need a simple, reliable and out of the box setup that make things work in the smallest amount of time. When you need something like this many sys admins have an excellent way to things in a tested and production prof way (specially if they are open mined to use open source); The Software Appliances The appliances are really helpful  but before you start using them you need to know a few things, so lets start by the bad:

1. Lack of flexibility
2. Hardware choices are often hard due to  the lack of drivers/modules available

The lack of flexibility is probably the biggest problem with appliances, usually they aren’t inflexible but to master the appliance you’ll have to put a big effort on the manuals, this should’ t be a problem if you stick to a few appliances but if you use a lot of them then you’ll probably take more time to master them than to study the OS and all the applications your need (apache, samba, iptables, and so on). About hardware choices, appliances are suited to run on most hardware out there (after all they use a linux kernel, at least most of them do) but if you run cutting edge hardware you may find it hard to make it work with your appliance, specially if your appliance version as more than 6month-1year. Let’s go to the good now:

1. Easy installation.
2. Fewer skills required.
3. Dedicated support, sometimes paid, usually free from the community.
4. Performance boost (In the cases where the appliance comes with it’s how hardware).
5. Security.

So in conclusion appliances can be a great help, but they need extensive planning and testing before going to a production environment. Think not only about the present needs of your client but also about the future and expected ones. Bellow I’m going to write about my favorite software appliances and what are they for.

1. dd-wrt - This is a great appliance for a bunch of Linksys, Asus, and another brand router, access point, home gateways, etc.
2. Endian FW – Probably the appliance I use the most, you need firewall with a proxy server with content filtering? Do you need a VPN server or an antivirus scanner for your internet connection? Try this one.
3. SME server – Do you need a windows domain server, a smtp server, pop server? Do you need to setup a small office in 2 hours? Choose SME server.

There are a lot of other appliances I’ve used since I’ve started working below a few honor mentions:

1. GeexBox – For multimedia content displaying
2. IPcop – Similar to endian (but endian has more features)

I’m done with appliances today, but you may wonder… what about the ugly? Well I didn’t find any that goes in this category, but the word goes well on the title :) . Cheers, Pedro Oliveira

Usually I write about technical stuff, or my rc cars, but this time I’m going to write about cloud computing, which isn’t that technical.

While reading two magazines today one had in the cover “Cloud computing you can’t afford to leave this one out” and the other “Cloud computing a must for every company”.

So, if your in IT certainly heard about cloud computing, but lets start by defining cloud computing; cloud computing is is a style of computing in which dynamically scalable and often virtualized resources are provided as a service over the Internet. Users need not have knowledge of, expertise in, or control over the technology infrastructure in the “cloud” that supports them (Wikipedia definition).

Having said this you probably are using the cloud, if you use gmail,hotmail, or something like that, apart from the mail service you may be using picasa storage, dropbox, or even HI5 or Facebook to share photos and if you use a blog is probable that’s on the cloud too.  But the cloud concept is wider. Imagine that your company as all the info on the cloud, all the applications that support your business, and that your systems are on the cloud too. You just leave your cheap PC clients, or thin clients, or whatever equipment you use to connect to the Internet and your piece of the cloud.

In theory this is a great tool, you won’t have to worry about uptime, backups, system maintenance, sys admins, power failures,air conditioning, but on the other end you’ll be dependent on your providers and your ISP. You won’t be free to change and you won’t be so versatile, your choices will be your providers choices and in the end applications and systems won’t be made to suit your needs but they’ll suit part of your needs and all your provider needs. Apart from that you’ll probably end spending more than you would if you had your own IT.

Sometime ago I was thinking in using amazon S3 for backing up my personal  data, photos, personal movies, my documents, as well as my family ones. Right now I’ve a BackupPC on a server to do it all and backing up about 3.5TB of info. With my usage profile amazon would cost me about 350€ a month, so as fast as I though in using amazon I lost the idea of using it, with 2 month of service I could buy a new server to do all the backup and with another month of service I could pay electric bill,space, and man work hour for a year.

Then a client that happily uses Sugar CRM, heard about “the cloud” and thought that easily could migrate sugar to SalesForce and all the applications on the company to Google Apps. So we asked for prices and the price of the cloud was about 960% more than the regular prices of applications and Sugar licenses, and this including all the system maintenance, space and electric costs.

So I started wondering, in the end I don’t see people pay less for the cloud usage, I see people having a smaller initial cost that in the end will be much greater than the original one.

I’m sure many of you had already made your own investigations about the cloud? Are you getting to the same conclusions?

Till now I’ve been writing  about costs, now lets get to  flexibility and limitations.

Usually when talking about the cloud everyone sells you that the cloud is flexible, that the cloud will suit your needs and that it will grow when your business grow and get smaller when your business is going through a bad time.

In the end your cloud won’t be that flexible, most of “cloud providers” will have well established limits on amount of CPU usage/time, there will be limits on bandwidth, limits on connections per second and if you need to pass those limits you’ll be paying a lot for it. Then the small letter of the contract, sometimes you can have more processor power because you needed it but then you have to keep it for the minimum period, sometimes a year or even more.

But well the cloud is cutting edge innovation so this is something worth paying for. Once again this isn’t totally true, IBM as a cloud scheme running for decades, corporate clients may pay for processor, MIPs, processor time and memory usage. Apart from IBM, other companies worked like this for ages, companies like HP, SUN, and others.

So what’s new? In my opinion the news are the way you interact with the cloud, making the browser the central part and unification point. The larger bandwidth available today also made this possible and the content is much richer.

I can see a really good usage for the home user who don’t want to worry with tech things, I see youtube, twitter, hi5, facebook and others growing and companies using those with a business mind, honestly I don’t see companies putting their secrets, their know how, their experience, and their core on the hand of a cloud, I may be wrong but right now I don’t see it moving that way (maybe I need glasses). I see a big fuss on the cloud as I’ve seen the .com bubble and IT recession, I’ve seen the thin-client revolution and the virtualization boom, now I see the cloud hype and in a few months or years something new will come up and all this will be forgotten. I’ll see companies moving towards a new hype and I investors spending they bucks on something else.

So to conclude; I don’t think the cloud is a must, I think it’s something that you already had with a different name, and  it became an hype because of a lot of marketing and publicity. If you think a little bit you’ll see who wins  with all the hypes, usually isn’t your company nor mine.

Cheers,

Pedro Oliveira