Cluster Install - need advice.

Message

BLASTER_ · Post by **BLASTER_** » Wed Feb 25, 2004 12:30 pm

I have 8 Pentium2 systems (3 450's and 5 350's) with 94megs of ram each. I would like to cluster them together for use as a general Linux server. (Apache, DNS, DHCP, MySQL, Postfix etc) as I dont have a budget for a more powerfull system. Each system has limited hardrive space (1.2g or more) except for the main system. each has 100mbps nic and a fast separated network for the cluster itself.

My question is: How can I use these system to get the best performance out of them for the app's I'm running?

I only have experience with OpenMosix, and I know I can get that working but I'm worried that Apache and MySQL wont migrate. In the very least with OpenMosix I'm going to be better off then I was (one single system alone) right? or are there stability issues I should be worried about? There is also other stuff out there, what about Round Robbin, MPI, or something else?

By the way - Can anyone better explain the OOM Killer, Poll/Select exceptions on pipes, and Load Limit options?

slon · Post by **slon** » Wed Feb 25, 2004 10:14 pm

Not technical but practical advice. 8 systems running will generate electrical bill that would cover a purchace of mobo+cpu combo at fry's and stick of RAM from some other retailer. Check out http://fatwallet.com for best deals.

BLASTER_ · Post by **BLASTER_** » Thu Feb 26, 2004 12:30 am

Its a non-critical buisnes deployment. Trust me, I would love more hardware but I have zero budget.

NewBlackDak · Post by **NewBlackDak** » Thu Feb 26, 2004 11:06 am

I think you'd be in MUCH better shape to take the harddrive and all but the minimum ram from one of the 350s, and put it in another. The one use stole from download Coyote, and set it up to be DNS and DHCP server. Put this HDD/Ram in one of the 450's, and make it the webserver. Use the machine with the most HDD for the MySQL server, and steal some more ram for it. This way you have hot-swap spares. If something goes wrong you just put the HDD in another machine and bring it back up, which is important when you have no budget for new machines.

I'm guessing since you have no budget then the mail server isn't gonna see enough traffic to warrant anything else. My mail server runs on a Gentoofied PowerMac 7600/120 with 72 MB of ram. OS is installed on a 2.1GB HDD swap is on a seperate 500MB HDD, and mail is stored on a 500MB external HDD that is backed up twice a day to a drive exactly like it. This serves 312 users. It just runs. The only time I ever even look at anymore is to add/delete users or to add a new spamassassin rule.

I have no idea how MySQL will work across mosix, but it's completely disk I/O bound, so reading across network would slow it down.
DNS, and DHCP servers would be silly for this.
I've seen Apache working, but there are much more graceful solutions to spread a web load.
I'm not sure about Postfix. Never seen it run on a cluster.

BLASTER_ · Post by **BLASTER_** » Thu Mar 18, 2004 10:11 am

I actualy went ahead with it and it is quite abit better than it was. Im really worried about stability issues.. but so far so good.. Ive seen process (like openmosixview) die off but none of the major ones have yet. (like apache)

I moved most of the ram to the main node and that seams to work better, but I have yet to put a ton of load on it.

I'll continue to test it and update this thread if I have problems.

silicondecay · Post by **silicondecay** » Thu Apr 08, 2004 12:00 am

I don't think that openmosix will do much for apache. Apache shouldnt be to processor intensive. The best thing for apache is ram for each new server spawned.

Openmosix didnt even speed up my build times, the compiler didnt run long enough to migrate processes.

While cool, running omtest on a 4 node cluster only cut the time in half, not into 1/4 like i would figure.

its bragging rights at any rate