Heh, we just discovered that mistake a few minutes ago….thanks though. I am now wondering and may run a test cluster with a separate 6 nodes and test how compaction is on very large data sets and such. We have tons of research data that sits there so I am wondering if 20T / node is now feasible with cassandra(I mean if mongodb has a 42T which 10gen was telling my colleague, I would think we can with cassandra).
Is there any reasons I should know up front that 20T per node won't work. We have 20 disks per node and this definitely has a different profile than previous cassandra systems I have setup. We don't need really any caching as disk access is typically fine on reads. Thanks, Dean From: Bryan Talbot <btal...@aeriagames.com<mailto:btal...@aeriagames.com>> Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org>> Date: Wednesday, February 20, 2013 1:04 PM To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org>> Subject: Re: cassandra vs. mongodb quick question(good additional info) This calculation is incorrect btw. 10,000 GB transferred at 1.25 GB / sec would complete in about 8,000 seconds which is just 2.2 hours and not 5.5 days. The error is in the conversion (1hr/60secs) which is off by 2 orders of magnitude since (1hr/3600secs) is the correct conversion. -Bryan On Mon, Feb 18, 2013 at 5:00 PM, Hiller, Dean <dean.hil...@nrel.gov<mailto:dean.hil...@nrel.gov>> wrote: Google "10 gigabit in gigabytes" gives me 1.25 gigabytes/second (yes I could have divided by 8 in my head but eh…course when I saw the number, I went duh) So trying to transfer 10 Terabytes or 10,000 Gigabytes to a node that we are bringing online to replace a dead node would take approximately 5 days??? This means no one else is using the bandwidth too ;). 10,000Gigabytes * 1 second/1.25 * 1hr/60secs * 1 day / 24 hrs = 5.555555 days. This is more likely 11 days if we only use 50% of the network. So bringing a new node up to speed is more like 11 days once it is crashed. I think this is the main reason the 1Terabyte exists to begin with, right?
