On Wed, Dec 10, 2008, nate wrote: >John Kordash wrote: >>> 2.) Use TCP, UDP Transmits are often slow these days. (mount >>> option tcp) >> >> Hmm, care to share any references for this? I'd be reaching for NFS over >> TCP in a long-haul type environment, but would run it over UDP otherwise. > >At least in my case, both of the vendors I am using for high >performance NFS (BlueArc, and Exanet) have tcp as a best >practice. Exanet actually runs on top of CentOS 4.4 though >does not use the linux NFS stack. We started using tcp with nfs about five years ago, largely to cure a problem where a system running SuSE 9.0 Pro with multiple IP addresses on the NIC was responding to NFS UDP packets from one of the aliased IP addresses, not the primary. This caused NFS mounts by OS X clients to fail as they expected to get the UDP packets back from the same IP to which they sent. Using tcp naturally fixed this, and I never got around to figuring out why the replies were coming from the aliases IP address. We use NFS mounted home Maildir directories on a system with about 10,000 e-mail accounts, and a cluster of 4 machines handling incoming e-mail, with most of the postfix configuration files NFS mounted as well. These handle about 100,000 incoming messages a day without problems (a fair number of which are dropped without delivery after checking with spamassassin). There are about 182,000 IMAP/POP3 daily logins to check mail. Load averages are fairly low on all the systems, and the incoming mail queues rarely get over five messages with most of the delivery time being spamassassin checking using a central bayesian database. The central server that has all the home directories generally runs with a load average around 0.50 (a 4-year old SLES 9.2 system with a single Intel(R) Pentium(R) 4 CPU 3.00GHz, 2GB RAM with 7,200 RPM Seagate Barracuda SATA drives, hardly a high performance machine compared to what we're building today. Bill -- INTERNET: bill at celestial.com Bill Campbell; Celestial Software LLC URL: http://www.celestial.com/ PO Box 820; 6641 E. Mercer Way Voice: (206) 236-1676 Mercer Island, WA 98040-0820 Fax: (206) 232-9186 There are three kinds of men. The ones that learn by reading. The few who learn by observation. The rest of them have to pee on the electric fence for themselves. -- Will Rogers