[Beowulf] Computation on the head node

[Perry E. Metzger]

Vlad Manea <vlad at geociencias.unam.mx> writes:
> On the other hand I do not want to see all may cluster idle waiting
> for the file server.  The w/r rate transfer for these NAS is ~30-40
> MB/sec which probably is a modest one.
>
> Do you have any recommendations for the file server?

I would suggest, again, that the only way to find out what your
application really needs is to benchmark. Some apps barely need to
talk to the disk and a slow NFS server is fine (or even better because
you can run diskless and save money which you can use for more
processing nodes). Some apps hammer the file system and need a local
drive, full stop. Some apps need only have reasonably slow networks,
some need insanely low latency and high throughput. Some apps need
fairly little memory, some need ast amounts. You won't know without
testing. It is unreasonable to pick a specific configuration until you
have tested.

> I think I need lots of RAM and fast disks. Since SCSI are expensive,
> are SATA disks OK?

I would say that, for most purposes, modern SATA drives are pretty
fast, but you may need to carefully tune things, regardless of the
type of hard drive, in order to achieve maximum performance. Of
course, for some applications, maximum drive performance is
unnecessary, and for some it is crucial. The biggest piece of advice
I can give you is *TEST BEFORE YOU DECIDE*.


-- 
Perry E. Metzger		perry at piermont.com