Well, thank you so much Thomas and everyone for your answers and invaluable feedback!
As a recap, I note that: - The current support of PFL is probably OK for our use-case, which is great. - We must be particularly careful with the event mask as some values may have significant impact on metadata performances. - Continuous monitoring of changelog size is definitely required. Best, Rémi Le 12/01/2023 à 15:17, thomas.leibov...@cea.fr a écrit : > Dear Rémi, > > Happy to see a new deployment of RobinHood in France in a sister company of > CEA :) > > Here are some answers to your questions: > > 1) I never measured precisely the impact of changelogs, but I'd say it is > not significant and not noticeable by users. AFAIR, I saw some presentations > talking about 5% of metadata performance degradation. > Perhaps Sebastien Buisson (in cc) who worked on using changelog for security > audit logs (which is more heavy than the default mask) can give us this > information. > > 2) Basically PFL makes Lustre use a different striping as a file grow (e.g. > stripe_count=1 for the first 10MB, then stripe_count=2 up to 1GB etc..), so > the beginning of the file may be located on different OSTs than the rest of > the file. > More info here: https://wiki.lustre.org/Configuring_Lustre_File_Striping > > rbh3 is aware of PFL, but only considers the current striping of the file > (not the first blocks). > A consequence is that the command like "rbh-find -ost xxx" may not report the > small blocks at the beginning of the file but only the current file striping > based on the current file size. > > 3) rbh4 is available here: > https://github.com/robinhood-suite > > For now it can only been used in scan mode, but the Lustre changelog reader > is close to be completed. We would be very happy if you beta test it! > My colleagues in cc will be happy to give you more information in needed. > We can schedule a call soon (in French) to discuss about it. > > Best Regards, > Thomas -- Rémi Palancher Rackslab: Open Source Solutions for HPC Operations https://rackslab.io _______________________________________________ robinhood-support mailing list robinhood-support@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/robinhood-support
