Sendmail On IBM Mainframes Running GNU/Linux

raffe writes: "Cnet reports that Sendmail has released a version of its e-mail server software that can run on Linux-powered IBM mainframe computers. In one benchmark test, IBM found that it was possible to house 2 million e-mail accounts on a single server, with 10 percent of the users accessing their mail at any given moment" For some reason though, IBM zSeries machines aren't listed at pricewatch ;)

Comments

The mainframe's not dead...

[Jay Maynard]

This is the kind of thing that mainframes do well: information processing with little or no actual computation. Their I/O abilities really make the difference here.

Hopefully, this kind of result will show the skeptics that there's a real purpose for the big boxes.

Re:What did they use to generate 400k users?

[valdis]

You did that with ONE system? Interesting - the Mirapoint results for 400K users needed:

• 2 POP server machines
• 5 SMTP router machines
• 10 message store machines
• 1 benchmark manager machine
• 1 mail sink machine
• 5 load generator machines

Dealing with 300K outbound postings is no biggie - I've been able to deal with that level on an old IBM RS6000-F30 (166mz 604). You don't need really big iron for outbound mail until you have more than 500K or so RCPT TO's on one piece of mail. It's mostly a matter of good queue management, and Sendmail 8.12 has new queue management code that makes it even easier (I should know, I tested it). The only real magic is not getting logjammed due to DNS waits and unreachable destinations.

On the other hand, having 40K people doing POP accesses while you're dumping mail into their mailboxes is trickier. Some of the more obvious issues:

• The obvious popd solution leaves you 40K processes running at once. This could be bad.
• Locking issues get interesting.
• Even with a journaling filesystem, you can get killed on the I/O. Remember that writing to a file means you also need to do stuff with the inode....