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From Ian Lea <ian....@gmail.com>
Subject Re: Lucene index on NFS
Date Tue, 02 Oct 2012 12:56:49 GMT
I agree that reliability/corruption is not an issue.

I would also put it that performance is likely to suffer, but that's
not certain.  A fast disk mounted over NFS can be quicker than a slow
local disk.  And how much do you care about performance?  Maybe it
would be fast enough over NFS to make the ease of deployment balance
out lesser speed.

What's the setup here?  Will you be writing to an index on local disk
of server A and reading it, over NFS, from server B (and C and ...) or
what?

--
Ian.


On Tue, Oct 2, 2012 at 1:45 PM, Paul Libbrecht <paul@hoplahup.net> wrote:
> I doubt NFS is an unreliable file-system.
> Lucene uses normal random access to files and this has no reason to be unreliable unless
bad things such as network drops happen (in which case you'd get direct failures or  timeouts
rather than corruption). I've seen fairly large infrastructures being based on NFS and corruption
is something I've never heard about.
>
> Note: no concurrent access to a lucene index, right?
>
> Paul
>
>
> Le 2 oct. 2012 à 14:01, Jong Kim a écrit :
>
>> Thank you all for reply.
>>
>> So it soudns like it is a known fact that the performance would suffer
>> rather significantly when the index files are accessed over NFS. But how
>> about reliability and robustness (which seems even more important)? Isn't
>> there any increased possibility for intermittent errors such as index file
>> corruption (due to cache inconsistency, difference in delete semantics,
>> etc.) when using NFS? Has anyone run into such trouble? Or is it strictly
>> just a performance issue?
>>
>> /Jong
>> On Tue, Oct 2, 2012 at 5:17 AM, Paul Libbrecht <paul@hoplahup.net> wrote:
>>
>>> My experience in the Lucene 1.x times were a factor of at least four in
>>> writing to NFS and about two when reading from there. I'd discourage this
>>> as much as possible!
>>>
>>> (rsync is way more your friend for transporting and replication à la solr
>>> should also be considered)
>>>
>>> paul
>>>
>>>
>>> Le 2 oct. 2012 à 11:10, Ian Lea a écrit :
>>>
>>>> You'll certainly need to factor in the performance of NFS versus local
>>> disks.
>>>>
>>>> My experience is that smallish low activity indexes work just fine on
>>>> NFS, but large high activity indexes are not so good, particularly if
>>>> you have a lot of modifications to the index.
>>>>
>>>> You may want to install a custom IndexDeletionPolicy.  See the
>>>> javadocs for details with specific reference to NFS.
>>>>
>>>>
>>>> --
>>>> Ian.
>>>>
>>>> On Tue, Oct 2, 2012 at 3:21 AM, Vitaly Funstein <vfunstein@gmail.com>
>>> wrote:
>>>>> How tolerant is your project of decreased search and indexing
>>> performance?
>>>>> You could probably write a simple test that compares search and write
>>>>> speeds of local and NFS-mounted indexes and make the decision based on
>>> the
>>>>> results.
>>>>>
>>>>> On Mon, Oct 1, 2012 at 3:06 PM, Jong Kim <jong.lucene@gmail.com>
wrote:
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> According to the Lucene In Action (Second Edition), the section 2.11.2
>>>>>> "Accessing an index over a remote file system" explains that there
are
>>>>>> issues related to accessing a Lucene index across remote file system
>>>>>> including NFS.
>>>>>>
>>>>>> I'm particuarly interested in NFS compatibility, and wondering if
>>> there has
>>>>>> been any work done to solve or mitigate this problem. Has this issue
>>> been
>>>>>> addressed? If not, are there some reliable work-arounds that make
this
>>>>>> possible at the expense of some sacrifice in other areas?
>>>>>>
>>>>>> Any information would be greatly appreciated, since my project heavily
>>>>>> depends on the feasibility of this.
>>>>>>
>>>>>> Thanks
>>>>>> /Jong
>>>>>>
>>>>
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>>>
>>>
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>>>
>
>
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