>From my experience, and what I've read, more the RAM the better. Any excess >memory can be used as disk cache, which should help with your reads a lot.
-Arindam -----Original Message----- From: Paolo Crosato [mailto:paolo.cros...@targaubiest.com] Sent: Tuesday, September 09, 2014 12:53 PM To: user@cassandra.apache.org Subject: RE: hardware sizing for cassandra 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.
