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groovin
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Joined: 07 Feb 2004
Posts: 429
Location: California, USA
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 Posted: Wed Jul 21, 2004 11:51 pm Post subject: openmosix question |
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i read on their site the following which makes me believe that a process can be worked on by two computers in the cluster:
| Quote: | | So when you start a program like bladeenc to convert Bach's .... from .wav to .ogg format, the openMosix routines on your machine compare the load on both nodes and decide that things will go faster if that process is sent from your Pentium-233 to his Athlon XP. This happens automatically: you just type or click your commands as you would if you were on a standalone machine. All you notice is that when you start two more coding runs, things go a lot faster, and the response time doesn't go down. |
so that something that normally takes alot of time can be done in less time. but then i read this (also from their site) which to me sounds contradictory:
| Quote: | openMosix lets a cluster of computers behave like one big multi-processor computer. However, it doesn't automatically parallelise programs. Each individual process only runs on one computer at a time. For example, if your computer could convert a WAV to a MP3 in a minute, then buying another nine computers and joining them in a ten-node openMosix cluster would NOT let you convert a WAV in six seconds. However, what it would allow you to do is convert 10 WAVs simultanously. Each one would take a minute, but since you can do lots in parallel you'd get through your CD collection much faster  . |
can anyone elaborate? i might just be misunderstanding... i ddid drink too much coffee today! thanks! |
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Lajasha
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Joined: 17 Mar 2004
Posts: 1040
Location: Vibe Central
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| Posted: Thu Jul 22, 2004 12:12 am Post subject: |
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| Quote: | What is openMosix not useful for?:
openMosix lets a cluster of computers behave like one big multi-processor computer. However, it doesn't automatically parallelise programs. Each individual process only runs on one computer at a time. For example, if your computer could convert a WAV to a MP3 in a minute, then buying another nine computers and joining them in a ten-node openMosix cluster would NOT let you convert a WAV in six seconds. However, what it would allow you to do is convert 10 WAVs simultanously. Each one would take a minute, but since you can do lots in parallel you'd get through your CD collection much faster .
If what you need to do is take a single process and parallelise it across multiple machines, then openMosix is probably not the technology you're looking for. |
Its basicly saying that you can give it multiple things to do and it will delgate who does it accourding to who is best suited and accross multiple pc's. So if you only have 1 proccess then only 1 pc works on it but you could then tell it to another thing and it would give it to the other pc and they would both be working at the same time.
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groovin
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Joined: 07 Feb 2004
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Location: California, USA
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| Posted: Thu Jul 22, 2004 5:02 am Post subject: |
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ahh, thanks for the reply. reading more carefully...
| Quote: | | Now while you're still typing ...., your roommate comes back, mumbling something about red chili peppers in cafeteria food. He resumes his tests, using a program called 'pmake', a version of 'make' optimized for parallel execution. Whatever he's doing, it uses up so much CPU time that openMosix even starts to send subprocesses to your machine to balance the load. |
before i was thinking along the lines of a single application was a single process... how dumb of me. didnt think that a single application can spawn subprocesses which could then be migrated to another cluster member. |
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metalh34d
Tux's lil' helper
Joined: 04 Feb 2004
Posts: 126
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| Posted: Fri Aug 27, 2004 1:28 am Post subject: |
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I am looking into starting my own linux server which will do my own dhcp, webhosting, ftp hosting and smpt experiments, with the add ons of dedicated network gaming services. Using openMoxis and a cluster I could turn 10 computers into 1 super smp server?
End result would be a centralized organization of a network but ran by several computers, correct? |
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groovin
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Joined: 07 Feb 2004
Posts: 429
Location: California, USA
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| Posted: Sat Sep 11, 2004 8:17 am Post subject: |
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metal,
it all depends on the process your running. some processes need shared memory, those processes will not migrate across cluster nodes so you will get no performance gain from a cluster.
linux clusters do not act like a mainframe, basically the cluster looks for the most under utilized cluster node to run a process and then migrates it to that one. a mainframe 'supercomputer' however, each processor in the system wil work on the same problem.
so, something like mysql will not migrate in a linux cluster, but postfix will. there is a list of apps that can migrate well and those that cannot. there is a patch (migshm) that allows openmosix to migrate some shared mem apps like apache. |
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