Hi all; I am considering hardware requirements for an MDS to be paired with a 500TB Lustre filesystem. I have a question regarding the sizing guidelines described in the manual.
For an anticipated average file size of 1MB, the MDT size guideline from section 21.3.2 works out to 4TB. For comparison, on our production 28TB Lustre filesystem, we have: # lfs df UUID 1K-blocks Used Available Use% Mounted on ufhpc-MDT0000_UUID 213655168 17329964 196325204 8% /ufhpc/scratch[MDT:0] ... filesystem summary: 29966190744 20728270148 9237920596 69% /ufhpc/scratch # lfs df -i UUID Inodes IUsed IFree IUse% Mounted on ufhpc-MDT0000_UUID 61049728 21416476 39633252 35% /ufhpc/scratch[MDT:0] ... filesystem summary: 61049728 21416476 39633252 35% /ufhpc/scratch My concern is that if I follow the guidelines, I would over-provision the MDS with space we would never use. I understand the inodes are pre-allocated and won't show up in the "Used" column above. Under what conditions would the actual MDT space get used more significantly? Thanks, Craig Prescott UF HPC Center _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
