#7: FS Design Around SMR: Seagate’s Journey and Reference System with EXT4

SMR is a gamechanger drive technology, embraced by all major manufacturers. SMR changes fundamental assumptions of filesystem management. This long-help abandonment of Random-Writes now makes drives behave as sequential-access tape. Seagate is leading the way in providing a standards compliant IO stack for use with the new drives. Using the new ZAC/ZBC commands to make and maintain a filesystem is essential for performant operation. Seagate is sharing lessons learned from modifiying EXT4 for use with SMR. This effort is called the SMR Friendly File System (SMRFFS). Learning objectives: 1) Forward-write only considerations for the block allocation scheme , 2) Zones/BlockGroup/AllocationGroup alignment and use , 3) Superblock, and other required write-in-place management schemes. Slides are available in the show notes at www.snia.org/podcasts.