On 7/14/11 11:34 PM, chris wrote: > Any comments on the configuration? Any experiences with iSCSI vs. Fibre > Channel for SANs and PostgreSQL? If the SAN setup sucks, do you see a > cheap alternative how to connect as many as 16 x 2TB disks as DAS?
Here's the problem with iSCSI: on gigabit ethernet, your maximum possible throughput is 100mb/s, which means that your likely maximum database throughput (for a seq scan or vacuum, for example) is 30mb/s. That's about a third of what you can get with good internal RAID. While multichannel iSCSI is possible, it's hard to configure, and doesn't really allow you to spread a *single* request across multiple channels. So: go with fiber channel if you're using a SAN. iSCSI also has horrible lag times, but you don't care about that so much for DW. -- Josh Berkus PostgreSQL Experts Inc. http://pgexperts.com -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
