On Thu, Nov 3, 2016 at 9:51 AM, Benjamin Toueg <btoueg@xxxxxxxxx> wrote: > > Stream gives substantially better results with the new server (before/after) Yep, the new server can access RAM at about twice the speed of the old. > I've run "bonnie++ -u postgres -d /tmp/ -s 4096M -r 1096" on both > machines. I don't know how to read bonnie++ results (before/after) > but it looks quite the same, sometimes better for the new, > sometimes better for the old. On most metrics the new machine looks better, but there are a few things that look potentially problematic with the new machine: the new machine uses about 1.57x the CPU time of the old per block written sequentially ((41 / 143557) / (16 / 87991)); so if the box becomes CPU starved, you might notice writes getting slower than on the new box. Also, several of the latency numbers are worse -- in some cases far worse. If I'm understanding that properly, it suggests that while total throughput from a number of connections may be better on the new machine, a single connection may not run the same query as quickly. That probably makes the new machine better for handling an OLTP workload from many concurrent clients, but perhaps not as good at cranking out a single big report or running dump/restore. Yes, it is quite possible that the new machine could be faster at some things and slower at others. -- Kevin Grittner EDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
