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From Vitaly Funstein <vfunst...@gmail.com>
Subject Re: RAM or SSD...
Date Thu, 19 Jul 2012 06:46:51 GMT
I was referring to *RAMDirectory*.

On Wed, Jul 18, 2012 at 11:04 PM, Lance Norskog <goksron@gmail.com> wrote:
>> You do not want to store 30 G of data in the JVM heap, no matter what
library does this.
> MMapDirectory does not store data in the JVM heap. It lets the
> operating system manage the disk buffer space. Even if the JVM says "I
> have 30G of memory space", it really does not. It only has address
> space allocated by the  OS but no memory.
>
> On Wed, Jul 18, 2012 at 10:39 PM, Toke Eskildsen <te@statsbiblioteket.dk>
wrote:
>> On Wed, 2012-07-18 at 17:50 +0200, Dragon Fly wrote:
>>> If I want to improve performance, which of the following is better and
why?
>>>
>>> 1. Buy a machine with a lot of RAM and use a RAMDirectory for the index.
>>
>> As others has pointed out, MMapDirectory should work better than
>> RAMDirectory. I am sure it will work fine with a relative small index
>> such as yours. However, it does not scale that well with index size.
>>
>>> 2. Put the index on a solid state drive.
>>
>> Why anyone buys computers without SSD's is a mystery to me. Use SSDs for
>> the small low-latency stuff and a secondary spinning drive for the large
>> slow stuff. Nowadays, a 30GB index (or 100GB for that matter) falls into
>> the small low-latency bucket. SSDs speeds up almost everything, saves
>> RAM and spares a lot of work hours optimizing I/O-speed.
>>
>> Regards,
>> Toke Eskildsen
>>
>>
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>
>
>
> --
> Lance Norskog
> goksron@gmail.com
>
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