Why not more than 32gb of RAM/node? Rahul Neelakantan
> On Sep 9, 2014, at 3:52 PM, Paolo Crosato <paolo.cros...@targaubiest.com> > wrote: > > Every node should have at least 4 cores, with a maximum of 8. Memory > shouldn't be higher than 32g, 16gb is good for a start. Every node should be > a phisical machine, not a virtual one, or at least a virtual machine with an > ssd hd subsystem. The disk subsystem should be directly connected to the > machine, no sans or fiber channel between. Cassandra is cpu and io bounded, > so you should get the maximum io speed and a reasonable number of cores. > > Number of nodes should be 3 at least with replication factor of 2. You should > prefer more less powerful nodes then fewer more powerful nodes. > > Disk size depends on your workload, although you should always keep 50% of > the disk free in the case repair sessions requires space, or perform sub > range repairs. > > In my experience a 1GB link between nodes is ok, but the less lag the better. > > Summing up if you need to save some money, get 4 cores and 16 gb or ram, 32 > is rarely needed and 64 a waste. 8 cores would probably be too much with 1000 > writes a second. > > Paolo > > > ........................................................................................ > Paolo Crosato > Software engineer/Custom Solutions > > > ________________________________________ > Da: Chris Lohfink <clohf...@blackbirdit.com> > Inviato: martedì 9 settembre 2014 21.26 > A: user@cassandra.apache.org > Oggetto: Re: hardware sizing for cassandra > > It depends. Ultimately your load is low enough a single node can probably > handle it so you kinda want a "minimum" cluster. Different people have > different thoughts on what this means - I would recommend 5-6 nodes with a 3 > replication factor. (say m1.xlarge, or c3.2xlarge striped ephemerals, I like > i2's but kinda overkill here). Nodes with less then 16gb of ram wont last > long so should really start around there. > > Chris > >> On Sep 9, 2014, at 11:02 AM, Oleg Ruchovets <oruchov...@gmail.com> wrote: >> >> Hi , >> Where can I find the document with best practices about sizing for >> cassandra deployment? >> We have 1000 writes / reads per second. record size 1k. >> >> Questions: >> 1) how many machines do we need? >> 2) how many ram ,disc size / type? >> 3) What should be network? >> >> I understand that hardware is very depends on data distribution and access >> pattern and other criteria, but I still want to believe that there is a best >> practice :-) >> >> Thanks >> Oleg. >
