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From Chris Lu <>
Subject Re: Very large number of indices in distributed environment
Date Thu, 04 Aug 2005 15:54:39 GMT
A big index is slow to merge, slow to search, and as you mentioned,
it's slow to sync. An 1G index took me several hours to merge on a P3
1GHz 512MRam.
Mounting Lucene on NFS is also a "No GO".

I feel you choice 2 may be feasible, although complicated. That's your
job, right. :)

BTW: I guess your app is a web hosted app for different users, is it?

Chris Lu
Lucene Search RAD on Any Database

On 8/4/05, Benjamin Reitzammer <> wrote:
> Hi,
> we are in the process of planning a search feature of a product and we
> are having quite a hard time figuring out the "right" way to do it.
> The requirements for our app are the following:
> 1) Large number of indices (at _least_ 10000)
> 2) The amount of data involved per index is not very high, but because
> of the number of indices involved the data set will be something about
> 500 - 1000 GB
> 3) The searching capabilities must be fail safe, while it's acceptable
> if deletes/updates can take some time.
> 4) The majority of operations will be searching the indices.
> I've followed the mailing list intensively the last month and
> especially the "Best Practices for Distributing Lucene Indexing and
> Searching" (
> and "Real time indexing and distribution to lucene on separate boxes (long)"
> (
> threads provided some interesting insight.
> But still our requirements are a bit different.
> My thoughts how the above could be handled, so far are:
> 1) Have one *really big* "master"  which handles all tasks related to
> index manipulation. Sync the indices according to Doug's tips
> out
> to a cluster of slaves that are responsible for searching.
> Problem: How to make sure that indices across  slaves are in sync.
> Big Problem: Syncing of this large number of indices will cause a lot
> of traffic and cause already quite a load on the slaves (not to speak
> of the master)
> 1.1) Is it safe to _search_ (only) an index mounted via NFS? If yes,
> then the search boxes could mount the indices on the master box. But
> this solution would probably lead to some serious perfomance issues
> because of the needed disk I/O on the master.
> Though I'd love to be proven wrong on this one.
> 2) Split up index collection into smaller portions and distribute a
> certain number of indices (~ up to 1000 indices) into smaller
> autonomous clusters, that are completely responsible for their
> collection of indices.
> Problem: How do I keep index distribution dynamic so I don't have to
> hardcode where to look for a certain index (that's not a real lucene
> issue, but more one of distributed computing, but nevertheless I
> thought you guys might know a way to solve it).
> Any ideas on this?
> Has anyone ever worked with such a large number of Lucene indices (and
> the amount of data it involves)?
> I appreciate your help very much.
> Cheers
> Benjamin
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