Multi Processors?????
 

We are upgrading our old UNIX system (dual 40MHz RISC), to a new Intel system with Red Hat 8.0.

Our budget is quite a bit were we could go for a 4 way XEON 900MHz (Dell, upgradeable to 8 Procs)
However a bloke selling IBM say go for 2 way 2.6GHz (No upgrade on procs)

Will RedHat support up to 8 processors?

Is 4 processors better than 2, what are the pros and cons with more processors.

We need something that will keep going for 10+ years.

We will be running an ERP system under an informix database with 50 - 70 users, database about 2GB in size.

Hope someone can help.

Multiple processors
 

From what I understand, the SMP Kernel (which ships with RH 8.0 iso's) supports up to 16 processors (tested with 4, possibly supports more than 16 theoretically).

In general, multiple processor systems start by having a specialized bus that all the processors share. As processing requests come in, either the first processor to pick it up takes it - or (in more advanced situations) the first processor manages the rest and evenly distributes processing among itself and the others.

With each processor added there is overhead to manage synchronization, assignment and other minor tasks. So two 300Mhz CPU's do not add up to one 600Mhz CPU. The one CPU machine will usually be faster. However if the major applications use parallel processing, the two processor machine would more likely be faster. It is something that needs to be weighed carefully.

In my opinion the type of processor matters a lot. What type of processor was the gentleman from IBM offering?

Pentium Xeon processors are nice for servers due to their larger L2 cache. They are tuned for server applications and constant processing environments.

Tip: The more processors you get, the more RAM you should have to help the processors. What usually happens is people are not doing enough processing on their servers to take up the available CPU power. Usually the slow down is Hard Disks or not enough RAM. Especially in your case, with a large database, the Hard Disk will be your concern. Four processors should be good with 1GB of RAM or more, preferably a SCSI/RAID setup for your Hard Disks would show the most differences in performance.

Plus a nice, high speed, network connection (Gigabit/Fiber) would help with a lot of users.

You may even think about splitting the power over 2 computers, each with 2/4 processors...

Good Luck
Leif

Xeon normally better
 

If you could get faster Xeons, I'd do that. The 2.4 kernel tops off at 8 processors--not that it cannot handle more, just that adding more doesn't help anyway.

Try looking at other vendors too. Compaq makes really good server boxes, and they have been supporting Linux for a long time. I've had poor success with PowerSludge boxes lasting as long as you are looking for.

Regarding IBM's statement--in the short term, the 2 2.6G P4 chips would probably be faster, mainly due to the older, slower P3-Xeons that you are looking at. If you can get the newer Xeons, you would definitely be better off that way. The large L2 cache really helps in DB applications.

In a DB application, the CPU isn't everything by a long shot. Make sure you get a good disk subsystem. Get a server system with multiple PCI busses so that you can put your disk subsystem on a different buss than the NIC and such.