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From Maxim Potekhin <potek...@bnl.gov>
Subject Re: Repair taking a long, long time
Date Tue, 19 Jul 2011 15:36:05 GMT
Thanks for pointer. As a comment to your disk speed comment --
I had already installed SSDs on these nodes.

Maxim


On 7/19/2011 9:41 AM, Edward Capriolo wrote:
>
>
> On Tue, Jul 19, 2011 at 7:24 AM, Maxim Potekhin <potekhin@bnl.gov 
> <mailto:potekhin@bnl.gov>> wrote:
>
>     We have something of the order of 200GB load on each of 3 machines
>     in a balanced cluster under 0.8.1.
>     I started repair about 24hrs ago and did some moderate amount of
>     inserts since then (a small fraction of
>     data load). The repair still appears to be running. What could go
>     wrong?
>
>     Thanks,
>     Maxim
>
>
>
> Repair calculates a merkle tree on each node and then transmits 
> differences to its neighbours.  Because this process run on all your 
> data it can take a LONG time.
> See http://wiki.apache.org/cassandra/LargeDataSetConsiderations
>
> Use 'nodetool compactionstats' and 'nodetool streams' to check the 
> progress. My rule of thumb is do not have more storage on a node then 
> you can compact in 3 hours. So for that you either need fast disks or 
> more nodes.
>


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