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E-mail demand jumps, outpaces expectations

by Dan Burrows

Although IS upgraded the Unix e-mail server last summer to a system that is roughly four times the machine we had available last year, the campus demand for e-mail has still outpaced the server capabilities. Several things have contributed to the slow res ponse noticed by campus members, including problems with e-mail aliases and an increase in message deliveries. During the quarter we made many adjustments to the server software that now appear to have improved the situation. We have also ordered additional equipment that will be available during January 1998.

E-mail alias problems

As a service to the campus, we set up e-mail aliases for each major this fall. When messages were sent out to the aliases, some of the recipients misunderstood the "reply" versus "group reply" options. Many people group replied, which caused others to e-mail comments that also used the group reply function. We actually had to shut down certain aliases for a while until things settled down. We have converted most of the aliases to list-servs, which handle group replies in a more efficient manner.

Message delivery jumps

Last year we averaged around 45,000 mail message deliveries a day. For Fall 1997, we will average about 75,000 messages a day. On some days, we delivered 100,000 e-mail messages during the alias situation described above.

IMAP usage grows

Usage of IMAP has grown quite a bit and we expect it to continue to do so. PCPine, Mulberry and other e-mail client software use the IMAP protocol to organize and allow reading of e-mail. IMAP has several versions, and we hope to upgrade to a more efficient one during the Christmas break week. We also believe we have tuned our e-mail server to handle IMAP more effectively, but will be watching as winter quarter progresses.

E-mail deliveries queued

To adjust the e-mail server response time, we traded immediate e-mail delivery for faster acceptance of incoming e-mail and service to client e-mail systems (both POP and IMAP). We are now queueing all e-mail deliveries, which causes a five minute delivery delay but has increased client service.

Once queued, e-mail delivery is affected by many things, such as the message length, the number of people who will receive the message, the use of aliases, the load on the system, etc. The net result is a different pattern of delivery speed and order from the prior behavior (usually in-order).

RAID disks to be added

We are working to obtain a RAID cluster for our disk service on the mail system. RAID has many advantages but is best known in terms of reliability and hot-sparing. However, it also provides much faster bandwidth to the disks, especially when writing to a disk. Right now our server is bottlenecked on disk writes and we expect to minimize this when we install the RAID disks.

Once the RAID cluster is installed we will again adjust the system to try to speed up e-mail delivery. We will keep you informed as we learn more about how this affects our e-mail service.

We appreciate your patience while we make the adjustments to provide a fast and reliable e-mail system. Comments are appreciated and may be sent to Dan Burrows (dburrows or x8846).

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Last Revised on 12/12/97 sab [an error occurred while processing this directive]