Hi Will, I could not answer you exact numbers, but yes, defragmentation in Windows is important, and it will speed up searches. I guess, that the ratio is determined by the number of file fragments. In Win environment I regularly run defragmentation, and usually I use drives for Lucene/Solr index where there's no too much other kind of files take place.
Péter http://eXtensibleCatalog.org 2010/12/8 Will Milspec <will.mils...@gmail.com>: > Hi all, > > Pardon if this isn't the best place to post this email...maybe it belongs on > the lucene-user list . Also, it's basically windows-specific,so not of use > to everyone... > > The question: does NTFS fragmentation affect search performance "a little > bit" or "a lot"? It's obvious that "fragmentation will slow things down", > but is it a factor of .1, 10 , or 100? (i.e what order of magnitude)? > > As a follow up: should solr/lucene users periodically remind Windows > sysadmins to defrag their drives ? > > On a production system, I ran the windows defrag "analyzer" and found heavy > fragmentation on the lucene index. > > 11,839 492 MB \data\index\search\_6io5.cfs > 7,153 433 MB \data\index\search\_5ld6.cfs > 6,953 661 MB \data\index\search\_8jvj.cfs > 5,824 74 MB \data\index\search\_5ld7.frq > 5,691 356 MB \data\index\search\_9eev.fdt > 5,638 352 MB \data\index\search\_8mqi.fdt > 5,629 352 MB \data\index\search\_8jvj.fdt > 5,609 351 MB \data\index\search\_88z8.fdt > 5,590 355 MB \data\index\search\_96l5.fdt > 5,568 354 MB \data\index\search\_8zjn.fdt > 5,471 342 MB \data\index\search\_5wgo.fdt > 5,466 342 MB \data\index\search\_5uo1.fdt > 5,450 340 MB \data\index\search\_5hrn.fdt > 5,429 345 MB \data\index\search\_6nyy.fdt > 5,371 353 MB \data\index\search\_8sob.fdt > > Incidentally, we periodically experience some *very* slow searches. Out of > curiousity, I checked for file fragmentation (using 'analyze' mode of the > nfts defragger) > > nota bene: Windows sysinternals has a utility "Contig.exe" whic allows you > to defragment individual drives/directories. We'll use that to defragmeent > the index direcotires > > will >
