[LON-CAPA-admin] Server Configuration Questions
korte at lite.msu.edu
Thu Jul 9 06:15:36 EDT 2009
On Jul 9, 2009, at 12:28 AM, Todd Ruskell wrote:
> We're getting some new hardware, and that has raised a couple
> questions I'd like to ask the community:
> 1) 32-bit or 64-bit build? Other than simply being able to access
> more memory per core, does that bring real performance advantages
> in LON-CAPA? Or are there other real performance advantages to
> moving to a 64-bit build? Or is it more like, "hey, it's 64-bit
> hardware, so why not?"
I would say so. You will have more throughput, and sooner or later,
you'll have to change anyway.
> We are currently 32-bit, so moving to 64-bit will require some file
> conversion, but that shouldn't be too bad.
Yes, this is fairly well tested by now. You have probably already
> 2) As some of you know, our IT folks are moving to a virtualized
> infrastructure. We currently have 1 library server and 2 access
> servers, each of which has dual-core hyperthreaded hardware.
> Although the servers are virtualized, the above hardware is
> dedicated to only the designated LON-CAPA server.
> The new hardware consists of blade servers with *lots* of cores, and
> even more memory. I've already been informed that we can't claim an
> entire blade each for the library and access servers :( but I can
> see that would probably be overkill.
This is somewhat odd, though. Virtualized blades?
> So finally the question: If you had the option, which of the
> following hypothetical situations is "better" for optimal
> performance? Would you prefer 1 monster virtual library server
> with 6 cores and 12 GB of RAM (or more if 64-bit). Or would you
> prefer 1 library and 2 access servers, each with 2 cores and 4 GB of
> RAM (all virtual, most if not all of the time running on the same
If it's the same blade, make it one monster library server to avoid
overhead. More servers make more sense if you have dedicated hardware
and dedicated DISKS.
> Or is there some other optimal distribution of cores and memory?
> In either case, the contents of /home are located on a SAN.
Yes, make it one monster library machine. Same blade, same connection
to the SAN ... makes no sense to split it.
> I do know that if we went to the single-server model we'd no longer
> be able to offer up our access server as spare machine, and we'd
> also not be able to offload users to another spare machine.
Why not? You can always offload. You can also offer your library
> Are there other reasons to stay away from a single "monster" machine?
> Back in the day when we were really limited to the number of cores
> per physical machine, having more than one machine made sense. But
> now it seems like having three virtual servers running on the same
> hardware is just adding an extra, unnecessary layer that slows
> things down.
That would also be my assessment.
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