<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML ><HEAD ><TITLE >File Systems</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK REL="HOME" TITLE="The openMosix HOWTO" HREF="index.html"><LINK REL="UP" TITLE="the openMosix FAQ" HREF="openmosixfaq.html"><LINK REL="PREVIOUS" TITLE="Kernel Questions" HREF="x1608.html"><LINK REL="NEXT" TITLE="Programming openMosix" HREF="x1661.html"></HEAD ><BODY CLASS="SECT1" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >The openMosix HOWTO: </TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="x1608.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" >Chapter 19. the openMosix FAQ</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="x1661.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="AEN1638" ></A >19.4. File Systems</H1 ><DIV CLASS="QANDASET" ><DL ><DT >19.4.1. <A HREF="x1638.html#AEN1642" > What's oMFS, how do I use, and where do I get it?:</A ></DT ><DT >19.4.2. <A HREF="x1638.html#AEN1657" > Can somebody explain to me the difference bewteen MFS and DFSA, and why I would need DFSA?:</A ></DT ></DL ><DIV CLASS="QANDAENTRY" ><DIV CLASS="QUESTION" ><P ><A NAME="AEN1642" ></A ><B >19.4.1. </B > What's oMFS, how do I use, and where do I get it?:</P ></DIV ><DIV CLASS="ANSWER" ><P ><B > </B > The openMosix File System (oMFS) is the filesystem used by openMosix kernels. You get it by installing an openMosix kernel on the nodes of your cluster with oMFS enabled in the kernel-config. (It should be enabled in the openMosix RPMs by default.)</P ><P > You should also enable Direct Filesystem Access (DFSA) which allows a migrated process to execute many syscalls on the remote node locally without the need to migrate it back to its home node.</P ><P > The use and administration of oMFS is very similar to NFS, but unlike NFS, oMFS features: <P ></P ><UL ><LI ><P > Cache consistency</P ></LI ><LI ><P > Timestamp consistency</P ></LI ><LI ><P > Link consistency</P ></LI ></UL > The DFSA layer on top of oMFS makes sure to move the process to the data, instead of vice versa, whenever it makes sense.</P ><P > Please read more about oMFS and how to use it in earlier chapters of the HOWTO. </P ></DIV ></DIV ><DIV CLASS="QANDAENTRY" ><DIV CLASS="QUESTION" ><P ><A NAME="AEN1657" ></A ><B >19.4.2. </B > Can somebody explain to me the difference bewteen MFS and DFSA, and why I would need DFSA?:</P ></DIV ><DIV CLASS="ANSWER" ><P ><B > </B > DFSA stands for Direct File System Access and is an optimization. It allows remote proccesses to perform some file system system calls locally rather then sending them to their home node. MFS stands for Mosix File System and allows all nodes access to all node filesystems. DFSA runs on top of a cluster filesystem, in this case MFS.</P ></DIV ></DIV ></DIV ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="x1608.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="x1661.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Kernel Questions</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="openmosixfaq.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Programming openMosix</TD ></TR ></TABLE ></DIV ></BODY ></HTML >