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From Ruchir Jha <>
Subject Re: Compression during bootstrap
Date Mon, 18 Aug 2014 11:22:13 GMT
On Wednesday, August 13, 2014, Robert Coli <> wrote:

> On Wed, Aug 13, 2014 at 5:53 AM, Ruchir Jha <
> <javascript:_e(%7B%7D,'cvml','');>> wrote:
>> We are adding nodes currently and it seems like compression is falling
>> behind. I judge that by the fact that the new node which has a 4.5T disk
>> fills up to 100% while its bootstrapping. Can we avoid this problem with
>> the LZ4 compressor because of better compression or do we just need a
>> bigger disk?
> 2TB per node is a lot of data. 4.5 would be a huge amount of data.
> Sure. Do you mean we should have started adding nodes before we got here?

> Do you mean "compaction" is falling behind? Do you setcompactionthroughput
> 0 while bootstrapping new nodes?
> I did a nodetool getcompactionthroughput and I got 0 MB/ s. It seems like
that just disables compaction throttling which seems like a good thingin my
scenario. Is that correct?

> I don't think "compression" is involved here? Why do you think it does?
 This is why I thought compression is involved:

Side note : we also increased number of concurrent compactors from 3 to 10.
Because we had a lot of idle CPU lying around but that's not helping
everytime we start bootstrapping we are still hitting 4.5 tb and them we
run out of disk space.


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