Linux – Software RAID speed

Having reshaped a RAID5 twice of as many weeks, I’ve found that adding a 2TB drive takes a good 36 hours, which is kind of frustrating.

After a bit of searching, I discovered that there is a setting in /sys/block/md*/md/stripe_cache_size which by default is set to 256. This is enough for normal day operations, but during a reshape I was seeing speeds around 16mb/s, which meant that it would take a long time to finish.

There are mixed results, some people run into issue if they increase the value beyond 1024, other people are not seeing problems until they go to 64k. There is a performance test here which show that the optimum speed is 8192, but then again this might vary due to other issues.

linked to

Try it out, it might help in your setup.


Missing …..

Most if not all of the photos in the posts are gone.. No I did not loose them, well kind of – on purpose…

After 5 years I felt that I needed some new [stag]hardware[/stag] for my server, and one of the things I decided was to move all my photos to smugmug, where they for a very small amount (current $ € exchange rate is on my side) host my photos (have a look).

Therefor all links to photos are in the posts, but the photos does no longer exist (still kind of).

But, I’m now a happy man, current OS ([stag]CentOS 5.2[/stag]), some new hardware, and I don’t have to care about my server for another 5 years.

Why I quit: kernel developer Con Kolivas

As a follow up on my comments in “Five crucial things the Linux community doesn’t understand about the average computer user”, I saw a reference to this interview with [stag]Con Kolivas[/stag] on /., who until recently was the maintainer of the -ck tree (linux kernel patch tree).

Even though people are already trying to bash each other with nifty comments about why, or why not Con is right in his statements.

There is one thing in this interview with stands out, and make the whole thing interesting. He did try, and he failed, for me (well I’m just a nobody) it looks like some of the kernel developers (sorry I’m not one of them, and I have to admit that most of them are very good at what they do) lack the perspective to be able to understand that they might not be doing the right thing – even if they actually are.

Many yeas ago I got my diploma as a software developer, and one of the things I learned doing that, is that the end user is always right (could also be the customer), that is as long as they do not want something which is obviously stupid.

Now we have a bunch of desktop users who would like to use GNU/Linux, but find that they a) lack support for their hardware b) they have the latest and brightest (which works), but still they don’t get the bang for their money. Well in that case, maybe the people who are responsible for what ever part of the kernel should have a look at it – yes the user might be wrong, and will be told off, but what if there is something wrong, can we afford that it does not get fixed?

In my humble opinion, we cannot afford to ignore the end user no matter how annoying it can be annoying to be told that ones code is rubbish by someone who doesn’t even know anything about programming……

“Five crucial things the Linux community doesn’t understand about the average computer user”

I wrote “The end of the Mac road”???, as a response to [stag]Ian Betteridge[/stag], now it seams that things have happened in “choose your OS” world….

Adrian Kingsley-Hughes from ZDnet have written a comment to “why does people still use Windows” discussion.

First installment: Five crucial things the Linux community doesn’t understand about the average computer user, second installment and follow up: Three more things that the Linux community doesn’t get.

The sad thing is that he is mostly right, how do you convince anyone to change to something they do not know anything, and btw. cannot promise that it will work.

Over the years I’ve have many and quite intense discussions with both sides of the fence so to say (I can be quite good at playing the devil advocate).

And what I have found is that, for the common user it is most of the time it’s ease of use which is the main thing, and there after applications, most people do not mind OpenOffice>, FireFox, and Thunderbird, but they want their OS to work – that is with all the weird hardware addons they can buy in the local hardware store.

For the corporate user; it a different story all together, companies mostly rely on applications which are not available for any other OS than the one they use. Sometimes they can get around it and move the applications to a web based solution, but that is not always the case, and in some cases that does not even help, as some web applications require Microsoft Internet Explorer (version x.xx, and not y.yy, with Microsoft JVM, and not Sun JVM, and specifically not IBM JVM).

As Adrian points out, there is a huge thing which most advocates for [stag]OpenSource[/stag] sometime forget; Support (not only the free variant), no one is willing to pay for support, that is the end user, corporations know that they need it, I know that for RedHat and Novell SuSE (SuSE Linux Enterprise Desktop) provide pay for support, and if one buys a box distribution for specifically for consumers there might be 90 days phone installation support, but it is not always the case (correct me if I’m wrong). And in most cases the support is based on installation only, not support for X usb device, or Y harddisk controler.

Then we are back at “what does Microsoft provide”, not much I’m afraid, but most hardware works with Microsoft (they probably sponsor hardware vendors), and “everyone knows Windows“, which means that if you buy into the Microsoft family you know that the next door neighbor probably will have a 15 year old kid who can help you for a small amount of money, or just for the kick of helping you out.

So what do we have left; we don’t want Microsoft Windows, and we cannot really get people to use GNU/Linux as it not ready for consumer use (I’m playing the devils advocate here), well there is Apple, they have a nifty thing called [stag]OSX[/stag] (pronounced: OS 10), which is Unix, with a (in my eyes) cool graphical interface, it works, and in many cases it’s very stable. Yes there might be some issues with hardware addon’s and other things, but in general terms it works. As Adrian points out you pay for it, it’s not being sold separately so you’ll have to by the hardware from Apple for a fairly high price – read: you buy in to Apple, and stay there, well that is a truth with modifications, these days you can run Microsoft Windows on your Mac (and also Linux), so do as the [stag]Apple[/stag] PC looks cool – a very expensive way to look cool, but we all have our faults.

Back to the question of [stag]GNU/Linux[/stag], well it have come a long way, someone pointed out to me the other week that Microsoft Windows 1.x wasn’t that workable either, and that it have come a long way – yes it have, and yes it does work in an environment where everyone plays by the rules, that is follow the standards, do not use any extensions which a specific to one OS only, then GNU/[stag]Linux[/stag] will work just fine, and when ever the Graphic Card vendors get around to write drivers which are working, then things would be even better. But we do not live in a perfect world (wouldn’t that be nice), so we have to adapt. I use GNU/Linux on one desktop as I have applications which only run on that, and I use Microsoft Windows when I need Microsoft Internet Explorer, and mostly I use OSX as that is the common nominator where most of everything works (in some way, with a bit help), and because I still have a terminal which can do what I need.

I wrote this on my Macbook Pro, using Firefox, sitting on my balcony – how cool is that:-)

As I was reading Slashdot I saw a link to this article on LinuxWorld AU about driver support on GNU/Linux, and it seams that things a moving forward on that issue.

And I did not even get around to moan about stability, viruses, and what ever other nasty things are out there, and why it’s “GNU/Linux” and not “Linux”.

“The end of the Mac road”???

I was reading this entry on Ian Betteridge blog, where he talks about his switch from [stag]OSX[/stag] to Gnu/[stag]Linux[/stag] ([stag]Ubunto[/stag]), not that I have any specfic issues with that.

But one thing which stands out was this sentence: “First up, let’s look at what this move is not: It’s not a protest against Apple, or a of criticism of Mac OS X or Apple hardware. Mac OS X is great: if you’re a non-technical user, and want everything to just work out of the box, it is almost certainly the the right choice for you.”

Wohhhh, most of the people I know who are using OSX are anything but non-technical, and yes he’s right it works, and it works out of the box, well isn’t that the reason why you would want something?? – I’m a geek (yes I finally did get around to admit to it), and I probably know more about Linux than any sane person should do, but that does not mean that I don’t want something which works (day in, day out). I’m also a great beleiver in [stag]OpenSource[/stag], as it most of the MacHeads I know (there is always someone who did not get the drift).

So lets settle the score;

OSX: 9
– still you need to know for a fact that your installation partition should be journaled

Linux: 7
– well if you have the right hardware, and have a recognized controler, and ….. – getting better, but there are a few things which needs to get sorted out

Upgrade (from a previous version of the OS)
OSX: 9
– put in the DVD boot, select what you want – not perfect, as your programs might have stopped working, but that does not happen very often

Linux: 5
– works as long as you did not blow of your right leg and install program or libraries from a diffrent source, and if it actually works you still need to spend time trying to get these programs to work again as your dependencies will have disapeared

Installation of Programs
OSX: 10
– download a DMG and do a drag and drop, how difficult can it be

Linux: 5
– I still cannot get around the fact that there is no common package format, even if you use RPM’s they are still only common to the specfic distribution

OSX: 10
– when ever I plug in an ethernet cabel it will stop using my wireless, if it finds a new wireless network when I travel (when it happens) it will ask me if I want to connect, never have to think about it, it just works

Linux: 6
– hummm, did you put your notebook to sleep, oh then you need to restart you network, oh you alread did that, have you tried to reboot, you did…. let me think about it…..

OSX: 11
– press powerbutton, press ‘s’….. open lid, type in password

Linux: -1
– don’t try this a home, it might work, that is if you have supported hardware, and you did modfy that configuration file

Actually Linux is not as bad as it might come out here, there are excelent distributions OpenSUSE, Ubunto, etc. And one have to remember that Apple controls everything, which makes it easier for them to make sure that everything works.

But people you have to agree that Linux is not always something which just work, there are issues which needs to get fixed, and as a road user, these issues might not be something I am looking to solve everytime I want to do something as simple as read my email (or write my blog as I do now).

On the other hand, Linux on servers is a great thing, on the desktop where you want to change something on a regular basis, could get you into trouble, but servers run for years (my box have had the same version for the last 3 years, and an average uptime of 6 – 9 months), it simply works. Yes it might not be as easy as OSX Server or the equivilent from this ‘small’ company based in Seattle. But once you get your head around it, it’s actually not that difficult.

Oh, thing I kind of forgot, more or less all the programs I used to use on my Linux desktop works on OSX, the very few which don’t have been replaced with similar ones. On top of that I got access to a hugh amout of stuff which I did not have before like iTunes🙂 make updating my iPod a dream…. Yes I know that a real OpenSource believer does not have an iPod as it is a closed source gadget….