FLASH drives do need a scheduler policy
Posted Sep 29, 2004 18:12 UTC (Wed) by BrucePerens
In reply to: It's not only RAM disks
Parent article: Modular, switchable I/O schedulers
FLASH drives like USB sticks have a limited write lifetime. They really should have a scheduler policy, that policty should be to keep frequently-written structures (superblock, FS metadata, directories) in core, consolidate their writes, and write them out infrequently. This is an area where we can come into conflict with the filesystem, which may have its own idea of what should be written atomicaly. BSD-style IO serialization (defining the order in which some critical data must be written, something like tagged queueing but for filesystems) might work best with this scheme, as it would communicate to the scheduler more information about what data it can freely re-arrange and what needs to have its order respected.
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