Hi, Having read the wiki page on Lustre's changelogs [1], I have a question about one claim "Use changelog entries to exactly replicate changes in a file system mirror."
Of the record types that the changelog supports, there is not an entry for WRITE, although one can see when files are created as CREAT is supported. So whilst the example that page allows me to establish that a file /mydir/hosts exists from 19:10:37 on 2010.03.24 , I know nothing about the contents of the file `hosts`. In order to implement the use case "Use changelog entries to exactly replicate changes in a file system mirror", you'd need something more than just the changelog... something that, for example, scp'd from the IO server the file /mydir/hosts elsewhere. Is there a common procedure for indeed doing this in Lustre? Or in fact have I missed something in the wiki page? Are the plans to support WRITE events in Lustre's changelogs? I'm not sure what that'd look like - you'd probably not want to overload a changelog with raw binary data. However, having read "Towards an I/O Tracing Framework Taxonomy" [2], I see that //Trace [3] does support replayable IO traces. Is replayable IO logging something that the Lustre community has, or intends on supporting in the future? [1] - http://wiki.lustre.org/manual/LustreManual20_HTML/LustreMonitoring.html [2] - http://www.pdsi-scidac.org/SC07/resources/KONWINSKI-PDSI_Paper-Towards_an_IO_Tracing_Framework_Taxonomy.pdf [3] - http://www.cs.cmu.edu/~droh/papers/trace-fast07.pdf -- Rob _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
