HPC and zfs.

[Michael Aronsen]

Hi,

On Feb 6, 2012, at 17:22 , Jeremy Chadwick wrote:
> - What single motherboard supports up to 192GB of RAM

Get an HP DL580/585 - they support 2TB/1TB RAM.

> - How you plan on getting roughly 410 hard disks (or 422 assuming
>  an additional 12 SSDs) hooked up to a single machine

Use LSI SAS92XX 4 (x4) port external controllers, and SuperMicro SC847E26-RJBOD1 disk shelves.
Each disk shelf needs 2 ports on the LSI controller, which means you get 90 disks per LSI card.
The DL580/585's have 11 PCIe slots, so you'd end up with 990 disks per server using this setup.

> 
> If you are considering investing the time and especially money (the cost
> here is almost unfathomable, IMO) into this, I strongly recommend you
> consider an actual hardware filer (e.g. NetApp).  Your performance and
> reliability will be much greater, plus you will get overall better
> support from NetApp in the case something goes wrong.  In the case you
> run into problems with FreeBSD (and I can assure you in this kind of
> setup you will) with this kind of extensive setup, you will be at the
> mercy of developers' time/schedules with absolutely no guarantee that
> your problem will be solved.  You definitely want a support contract.
> Thus, go NetApp.

We have NetApp's at our University for home storage, but I would struggle to recommend them for HPC storage.

A dedicated HPC filesystem such as Lustre or FhGFS (http://www.fhgfs.com/cms/) will almost certainly give you better performance as they're purpose made.

We use FhGFS in a rather small setup (44 TB usable space and ~200 HPC nodes), but they do have installations with 700TB+.
The setup consists of 2 metadata nodes and 4 storage nodes, all supermicro servers with 24 WD Velociraptor 600 GB 10K RPM disks.
This setup gives us 4.8GB/sec write and 4.3GB/sec read speeds, all for a lot less than a comparable NetApp solution (we paid around €30.000).
It now has support for mirroring on a per folder level for resilience.

Currently it only runs on Linux but i'm considering a FreeBSD port to get ZFS for volume management and now that OFED is in FreeBSD 9, Infinifband is possible.

I'd highly recommend a parallel filesystem, unfortunately not many, if any, are available on FreeBSD at this time.

Regards,
Michael