Re: high throughput storage server?

with more network cards = more network gbps
with better (faster) rams = more disks reads
with more raid0/4/5/6 = more speed on disks reads
with more raid1 mirrors = more security
with more sas/sata/raid controllers = more GB/TB on storage
with more anything ~= more money
just know what numbers you want and make it work

2011/2/17 John Robinson [off-list ref]:

On 14/02/2011 23:59, Matt Garman wrote:
[...]

quoted

The requirement is basically this: around 40 to 50 compute machines
act as basically an ad-hoc scientific compute/simulation/analysis
cluster.  These machines all need access to a shared 20 TB pool of
storage.  Each compute machine has a gigabit network connection, and
it's possible that nearly every machine could simultaneously try to
access a large (100 to 1000 MB) file in the storage pool.  In other
words, a 20 TB file store with bandwidth upwards of 50 Gbps.

I'd recommend you analyse that requirement more closely. Yes, you have 50
compute machines with GigE connections so it's possible they could all
demand data from the file store at once, but in actual use, would they?

For example, if these machines were each to demand a 100MB file, how long
would they spend computing their results from it? If it's only 1 second,
then you would indeed need an aggregate bandwidth of 50Gbps[1]. If it's 20
seconds processing, your filer only needs an aggregate bandwidth of 2.5Gbps.

So I'd recommend you work out first how much data the compute machines can
actually chew through and work up from there, rather than what their network
connections could stream through and work down.

Cheers,

John.

[1] I'm assuming the compute nodes are fetching the data for the next
compute cycle while they're working on this one; if they're not you're
likely making unnecessary demands on your filer while leaving your compute
nodes idle.

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Roberto Spadim
Spadim Technology / SPAEmpresarial
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