On Mon, Aug 30, 2010 at 10:11:32PM -0700, Christopher George wrote: > > I was wondering if anyone had a benchmarking showing this alignment > > mattered on the latest SSDs. My guess is no, but I have no data. > > I don't believe there can be any doubt whether a Flash based SSD (tier1 > or not) is negatively affected by partition misalignment. It is intrinsic > to > the required asymmetric erase/program dual operation and the resultant > RMW penalty to perform a write if unaligned. This is detailed in the > following vendor benchmarking guidelines (SF-1500 controller): > > http://www.smartm.com/files/salesLiterature/storage/AN001_Benchmark_XceedIOPSSATA_Apr2010_.pdf > > Highlight from link - "Proper partition alignment is one of the most critical > attributes that can greatly boost the I/O performance of an SSD due to > reduced read modify‐write operations." > > It should be noted, the above highlight only applies to Flash based SSD > as an NVRAM based SSD does *not* suffer the same fate, as its > performance is not bound by or vary with partition (mis)alignment.
Here's an article with some benchmarks: http://wikis.sun.com/pages/viewpage.action?pageId=186241353 Seems to really impact IOPS. Ray _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
