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 <john.robinson@xxxxxxxxxxxxxxxx>: > On 14/02/2011 23:59, Matt Garman wrote: > [...] >> >> 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. > > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Roberto Spadim Spadim Technology / SPAEmpresarial -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
