Thank you all for the suggestions, The OS is not windows, it's centos, a colleague thinks that even on linux defragmenting can improve performance about 2X because it keeps the data contiguous on disk.
We cannot use flashcache because we run solr on virtual machines. We will investigate better on the memory suggestion by Shawn.. thank you very much. Danilo Danilo Tomasoni Fondazione The Microsoft Research - University of Trento Centre for Computational and Systems Biology (COSBI) Piazza Manifattura 1, 38068 Rovereto (TN), Italy tomas...@cosbi.eu<https://webmail.cosbi.eu/owa/redir.aspx?C=VNXi3_8-qSZTBi-FPvMwmwSB3IhCOjY8nuCBIfcNIs_5SgD-zNPWCA..&URL=mailto%3acalabro%40cosbi.eu> http://www.cosbi.eu<https://webmail.cosbi.eu/owa/redir.aspx?C=CkilyF54_imtLHzZqF1gCGvmYXjsnf4bzGynd8OXm__5SgD-zNPWCA..&URL=http%3a%2f%2fwww.cosbi.eu%2f> As for the European General Data Protection Regulation 2016/679 on the protection of natural persons with regard to the processing of personal data, we inform you that all the data we possess are object of treatment in the respect of the normative provided for by the cited GDPR. It is your right to be informed on which of your data are used and how; you may ask for their correction, cancellation or you may oppose to their use by written request sent by recorded delivery to The Microsoft Research – University of Trento Centre for Computational and Systems Biology Scarl, Piazza Manifattura 1, 38068 Rovereto (TN), Italy. P Please don't print this e-mail unless you really need to ________________________________ Da: Walter Underwood <wun...@wunderwood.org> Inviato: lunedì 22 febbraio 2021 18:25 A: solr-user@lucene.apache.org <solr-user@lucene.apache.org> Oggetto: Re: defragmentation can improve performance on SATA class 10 disk ~10000 rpm ? [CAUTION: EXTERNAL SENDER] [Please check correspondence between Sender Display Name and Sender Email Address before clicking on any link or opening attachments] True, but Windows does cache files. It has been a couple of decades since I ran search on Windows, but Ultraseek got large gains from setting some sort of system property to make it act like a file server and give file caching equal priority with program caching. wunder Walter Underwood wun...@wunderwood.org http://observer.wunderwood.org/ (my blog) > On Feb 22, 2021, at 9:22 AM, dmitri maziuk <dmitri.maz...@gmail.com> wrote: > > On 2021-02-22 11:18 AM, Shawn Heisey wrote: > >> The OS automatically uses unallocated memory to cache data on the disk. >> Because memory is far faster than any disk, even SSD, it performs better. > > Depends on the os, from "defragmenting solrdata folder" I suspect the OP is > on windows whose filesystems and memory management does not always work the > way the Unix textbook says. > > Dima
