> Maybe, I was talking generally about the concept of > content-addressable storage, not venti in particular. I believe it's > possible to do CAS without a major performance hit, look at ZFS, for > example.
do you have any reference to ZFS being content-addressed storage? > >> I'm of a completely different opinion regarding fragmentation. On > >> SSDs, it's a non issue. > > > > that's not correct. a very good ssd will do only about 10,000 r/w random > > iops. (certainly they show better numbers for the easy case of compressable > > 100% write work loads.) that's less than 40mb/s. on the other hand, a > > good ssd will do > > about 10x, if eading sequentially. > > Sure, but 1,000 iops gives you only a 10% performance hit. With > rotating rust 10 iops give you the same 10% hit, two orders of > magnitude difference. In my experience, even if you are ignoring the > fragmentation issue completely, your files will be less than 100 times > more fragmented compared with a traditional filesystem so your system > overall will be less affected by fragmentation. your claim was, random access is free on ssds. and i don't see how these numbers bolster your claim at all. - erik
