On Tue, Jan 6, 2015 at 10:31 PM, Eric Sandeen <sandeen@xxxxxxxxxxx> wrote: > On 1/6/15 1:55 PM, Chris Murphy wrote: >> What's sectsz= used for? Historically this would be sectsz=512, >> bsize=4096 before AF hard drives appeared. So is sectsz used for >> optimizing sub blocksize changes? e.g. if only 50 bytes needs >> changing, the fs doesn't need to read modify and write the entire 4096 >> block, just change the affected sector? > > Nope, filesystem data blocks are always fully written, but the sector > size is i.e. the minimum _log_ IO size. So maybe the people reporting performance problems with sectsz=512 on AF drives compared to manually specifying 4096 bytes, have a high metadata workload with older AF drives and are getting lot of in-drive RMW... -- Chris Murphy _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
