> content addressed means given the content, you can generate the address. > this is NOT true of zfs at all.
How come? With venti, the address is the SHA-1 hash, with ZFS, you get to chose the hash, but it can still be a hash. > you keep changing the subject. your original claim was that random > access is not slower than sequential access for ssds. you haven't backed > this argument up. the relative performance of ssds vs hard drives > and caching are completely irrelevant. My original claim was that fragmentation is a non issue if you have SSDs. I still claim this and I expanded on the context in my previous post. Of course that random I/O is slower than sequential I/O, SSD or not, but in practice, filesystem fragmentation causes an amount or random I/O much less than what a SSD can handle, so throughput in the fragmented case is close to the throughput in the sequential case. I don't think that caching is completely irrelevant. If I have to chose between a complex scheme that avoids fragmentation and a simple caching scheme that renders it irrelevant for a particular workload, I'll chose the caching scheme because it's simpler. -- Aram Hăvărneanu
