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From aaron morton <>
Subject Re: Disk configuration in new cluster node
Date Fri, 21 Sep 2012 01:05:11 GMT
> Would it help if I partitioned the computing resources of my physical machines into VMs?

Just like cutting a cake into smaller pieces does not mean you can eat more without getting

In the general case, regular HDD and 1 Gbe and 8 to 16 virtual cores and 8GB to 16GB ram,
you can expect to comfortably run up 400GB of data (maybe 500GB). That is replicated storage,
 so 400 / 3 = 133GB if you replicate data 3 times. 
Hope that helps. 

Aaron Morton
Freelance Developer

On 19/09/2012, at 3:42 PM, Віталій Тимчишин <> wrote:

> Network also matters. It would take a lot of time sending 6TB over 1Gb link, even fully
saturating it. IMHO You can try with 10Gb, but you will need to raise your streaming/compaction
limits a lot.
> Also you will need to ensure that your compaction can keep up. It is often done in one
thread and I am not sure if it will be enough for you. As of parallel compaction, I don't
know exact limitations and if it will be working in your case.
> 2012/9/18 Casey Deccio <>
> On Tue, Sep 18, 2012 at 1:54 AM, aaron morton <> wrote:
>> each with several disks having large capacity, totaling 10 - 12 TB.  Is this (another)
bad idea?
> Yes. Very bad. 
> If you had 6TB on average system with spinning disks you would measure duration of repairs
and compactions in days. 
> If you want to store 12 TB of data you will need more machines. 
> Would it help if I partitioned the computing resources of my physical machines into VMs?
 For example, I put four VMs on each of three virtual machines, each with a dedicated 2TB
drive.  I can now have four tokens in the ring and a RF of 3.  And of course, I can arrange
them into a way that makes the most sense.  Is this getting any better, or am I missing the
> Casey
> -- 
> Best regards,
>  Vitalii Tymchyshyn

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