sams on poweredge 2450 - dell usa€¦ · web viewthis is a study of sendmail advanced messaging...

Scaling Sendmail® Advanced Messaging

Server on Dell™ PowerEdge™ 2450

Enterprise Systems Group (ESG) Storage Systems Group (SSG)

Dell White Paper

By J. EllisESG/SSG Technical Marketing

February 2001

ContentsAbstract...............................................................................................3Executive Summary.............................................................................4

Introduction............................................................................................4The Market for email.............................................................................4Sendmail and SAMS...............................................................................5SAMS Product Line Benefits.................................................................5Test Environment...................................................................................6Conclusions.............................................................................................7

Messaging Background.......................................................................8Email........................................................................................................8POP...........................................................................................................9IMAP.......................................................................................................10SMTP......................................................................................................10Email clients.........................................................................................11Email addressing..................................................................................13

Load Testing......................................................................................14System configurations.........................................................................14Test users..............................................................................................15Load simulation....................................................................................15POP loads...............................................................................................15IMAP loads............................................................................................15

System information...........................................................................15Sendmail configuration.......................................................................15Power......................................................................................................15RAID.......................................................................................................15Backup...................................................................................................15

Appendix A........................................................................................15Glossary.................................................................................................151500 IMAP users..................................................................................153000 IMAP users..................................................................................154000 POP users.....................................................................................158000 POP users.....................................................................................1515000 POP users..................................................................................15

Sendmail Contact Information..........................................................15Acknowledgements and Copyrights.............................................................15

February 2001 Dell ESG/SSG

Section 1Abstract

This paper presents the results of a study of the electronic mail storage product from Sendmail®: Sendmail Advanced Messaging Server (SAMS). SAMS provides a highly tuned mail server that is designed for ease of maintenance. The message server has been customized, along with the Dell™ PowerEdge™ 2450 server, into a number of bundles aimed at providing email for different tiers of supported users. The study shows various hardware configurations to support the number of mail users associated with each tier.

This paper outlines test methodology and results, and discusses the background for this form of electronic mail. It also presents information on the growing need for offerings such as this Dell Sendmail bundle. The study shows that the performance per dollar of the Dell PowerEdge 2450, along with the tailored SAMS system, offers a cost competitive system for electronic mail.


Section 2Executive SummaryIntroduction

Use of the Internet has grown, and will continue to grow, at a fast pace. In addition to there being simply more users, there are new uses being found. There are growing opportunities for new services such as hosting applications for a number of users – the Application Service Providers (ASP) market. Part of the explosion in electronic information exchange is that of electronic mail, or email. Whether a company is adding or expanding its email infrastructure, or offers email hosting to other companies, the infrastructure required support email solutions continues to grow rapidly. Part of Dell’s aim is to provide complete, cost effective packages to help enable this growth. Dell’s Internet Partner Division, (IPD), delivers solutions tailored to the unique needs of this market. IPD works with premiere software solution partners to provide customized offerings built on Dell’s leading edge systems.

Dell, working with Sendmail Inc., has tailored a set of turnkey email server solutions. These system bundles have been tested under various mail loads and provide three sizes of mail server offerings. Each comes pre-installed and ready to be configured for use.

The Market for emailIn the rapidly expanding market for electronic mail, the Simple Mail Transfer Protocol (SMTP), along with Post Office Protocol (POP) and Internet Message Access Protocol (IMAP) are some of the most commonly used protocols. The growth in email requires larger amounts of server resource to be used in this area. SMTP provided an early base for the exchange of text-based mail, and its ability to carry attachments to email has given it the flexibility to continue to provide a flexible mail delivery system. Even with propriety mail systems such as Microsoft Exchange or Lotus Notes, there is still a substantial and growing amount of mail running through SMTP. Driven by this growth in SMTP, there are a growing number of companies that offer to host a company’s email requirements, usually for a setup and per mailbox fee. There is market opportunity for reliable mail servers that provide a low cost per-mailbox solution.

Sendmail and SAMSThe utility sendmail has been available on UNIX systems for a long time for managing email messages. The company, Sendmail, has expanded and built on this base to produce its Sendmail Advanced Message Server (SAMS). This has been designed to provide a


reliable, fast, and easy to manage mailstore, reducing the runtime maintenance. SAMS provides modular Internet message hosting with a standards-based architecture. It is designed to provide seamless scalability, reliability, anytime-anywhere access, and ease of administration.

SAMS is designed to let service providers buy what they need now and expand their system as business needs require. SAMS may help service providers to:

Cut time-to-market and maximize short-term ROI with quick and cost-effective deployment.

Scale rapidly to match business growth while maintaining quality and reliability.

Contain personnel costs for system deployment and administration.

Deliver value-added, multi-tier services to acquire, retain, and upgrade subscribers.

SAMS Product Line Benefits SAMS flexible, standards-based architecture and proven technology (the technology has been the base of email systems for twenty years) are built on open standards by a team that has also contributed to the development of Internet protocols that make the Internet. True to Sendmail's Open Source roots, it's designed for smooth integration with other standards-based technologies.

SAMS scalable architecture can help organizations meet current needs cost-effectively, then grow invisibly to users without system-wide replacements. The Dell/Sendmail pre-configured bundles incorporating the PowerEdge 2450 can support tens of thousands of users.

SAMS is designed for performance. It contains multithreaded POP and IMAP servers, a partitionable message store, and a high-speed database. Sophisticated indexing and caching is designed to accelerate message access, avoid I/O bottlenecks, and maximize CPU use. Efficient message processing – such as storing multi-recipient messages as a single instance and not spawning a new process for each message – minimizes server load and boosts performance.

Both SAMS message store and the Dell Power Edge 2450 are designed to minimize downtime. Online backup and storage reconfiguration allows users to add capacity on the fly. It also incorporates the sendmail Mail Transfer Agent (MTA). Sendmail's IMAP server and optional Webmail and wireless capabilities give users anywhere, anytime access to messages, synchronized across devices.

The Dell/Sendmail Message Server, SAMS, provides an out-of-the-box solution that's pre-installed and quick and easy to configure. It is designed to ease the administration burden with secure web-based


remote administration, delegated domain and account management, and user-friendly interfaces, tools, and wizards.

SAMS modular components include multi-threaded IMAP4 and POP3 servers, a proven message store, the Sendmail MTA (a de-facto standard on Unix-based mail systems), a LMTP server, an authentication server, LDAP integration and intuitive web-based administration tools.

The study that is documented here put SAMS together with the Dell PowerEdge 2450 server running Red Hat Linux to provide three tiered mail server offerings, as follow:

4000 POP users 1500 IMAP or 8000 POP users 3000 IMAP or 15000 POP users

The results of the study have shown that the combination of Linux on the Dell PowerEdge 2450 gives a low cost, reliable base running on a highly available Intel architecture-based server.

Simulated mail loads were run against the three configurations and their load, response time and accuracy were measured to form the basis of the configuration's capability.

Test EnvironmentAfter defining the mail loads to be used in the testing, three configurations of the Dell PowerEdge 2450 were established. These systems were setup and run against mail test clients by Dell in one of their Application Solution Center laboratories. Simulated mail users were generated with Mozilla’s mstone tool (http://www.mozilla.org/projects/mstone). This test tool, along with the per configuration test scripts, allowed for the measurement of various response times related to a mail system’s interaction with its user. To provide sufficient load on the mail server, a number of clients running the mstone tool were run against them. The basic test architecture is shown in Figure 1.


http://www.mozilla.org/projects/mstone

Figure 1 -- Test Architecture

The way that the load was divided between clients was to spread the simulated mail users across them. As each mail user on a running system would vary in the load that they present, so too does the load presented by the simulated clients.

Typical mail users don’t simply get a set amount of mail, or get their mail at a set time. Configuration of the tests attempted to represent these variations while allowing a test environment that is sufficiently defined to be reproducible.

ConclusionsThe three mail server configurations that are presented provided quickly and simply installed and configured mail servers. These mail systems were easily maintained through their web based GUI administration interface, or through a command line interface. Once unpacked, the system is configured for the mail domains it is to support, has its users added, and then it’s ready to go. Through the testing presented here it was determined that the systems easily met their performance requirements.


s r e c t i o n 2

Section 3Messaging BackgroundEmail

The amount of email being generated has been rapidly increasing for years. This is not slowing down, and with greater expansion of the World Wide Web (WWW) the amount of users requiring email facilities will continue to grow.

Email is being used as a significant marketing tool. As more and more people use the Web as part of their daily lives, acquiring email addresses, this will continue. With address lists being readily available, along with information about a user’s Web habits, targeting email becomes simpler. The automated nature of email, which avoids the costs of printing/postage etc., lends itself to large distributions of any given communication. There are other opportunities – such as companies offering newsletters or special discounts to subscribers – all keeping the company’s name in front of potential buyers. Companies are increasingly using email within their organizations, often providing email access to employees that previously wouldn’t have access to such a means of communication. More and more individuals are making use of the web to send and receive personal mail.

Along with one-to-one, or one-to-few email messages, the rise of one-to-many distributions creates proportionally more data. For the majority of mail on the Web, each recipient of a message gets the whole of the message text. This means that one note sent out to a distribution list will take up some of the resources on the many email servers that the various recipients use. The requirement for such server resources is growing much faster than simply the increasing rate at which notes are being sent.

Another trend that is requiring more mail server resources is the type of message being sent. Traditional text based messages are moving toward more sophisticated formats, such as HTML. More and more exchanges of files between users are being done as attachments to email messages – which can lead to the size of email messages varying wildly. The amount of space a user’s mailbox, or even single mail item, takes up leads to the administrative tasks and policy decisions required to administer the server.

Two ways of distributing the data within an email lead to two types of mail system architecture. When sending a note to a recipient, the amount of data that the note takes up will need to be generated, transmitted and stored on some mail system. With a widely distributed system, sending the complete item, although more resource intensive, is more reliable. Within a more closely controlled


environment, mail can be stored on a server and pointers to its presence on that server can be sent out to the recipients. This will save storage space on the mail server, but requires closer integration between the client and server to administer the sharing required. This type of system is likely to take up more processing resource on the server when retrieving the mail.

Basic text email has always been integral to Unix systems. As these are multi-user systems, exchanging messages between users on a host, or on different hosts, was a clear need. These mail exchanges led to a number of different delivery schemes as well as a means for addressing the mail. Two of the commonly used mechanisms to provide a user access to their mail are Post Office Protocol (POP) and Internet Message Access Protocol (IMAP). Frequently when a new user is setting up access to their email they’ll be required to know the name of their mail server and whether to access it via POP or IMAP. A related protocol, Simple Mail Transfer Protocol (SMTP), defines delivery of mail to a user’s server.

POPPOP is the earlier and simpler of the two mail access protocols discussed here. Version 3 is the current implementation, and so the mail server is often referred to as POP3. Being a simpler protocol than IMAP, it uses fewer resources on the server, but lacks some of IMAP’s features. A mail server running POP3 listens for incoming requests on port 110 – a “well known” TCP port. A “well known” port is one established as having a particular function. The mail client will contact the server’s port and establish a connection by providing the user’s email ID and password. Once connected, the mail client can query the mail waiting for the user and download it. Once each mail item is downloaded to the client it can be deleted from the server or left in place. If it is left on the server it will keep occupying drive space, of which the user or the server may be limited. Automatic deletion of the messages can lead to problems if users used more than one system for accessing their mail. Access of mail from one client would store the mail on that client, and it would no longer be on the server for download if a user were to use a second client. This leads to multiple partial mailboxes, which is not a problem if users always accessed their mail from a single client. Its simplest use would be from a single client for a given user who would have the mail client delete the server copy of the mail as its downloaded.

The interaction that the mail client has with the server can also be generated from a telnet session to the server. Though not useful for actually accessing mail, it can be of use in testing out a mail server. This access is discussed in the following book: Sendmail for Linux, Richard Blum, SAMS Publishing, April 2000.

POP3 is documented in RFC 1939. Requests for Comments (RFC) are standards that can be at one of various stages through their approval process. They’re freely available from a number of repositories such as that of the Internet FAQ consortium at http://www.faqs.org/rfcs/. This protocol is currently widely used for Internet based mail.


http://www.faqs.org/rfcs/

IMAPRather than having the mail server simply deliver the mail to the client as with POP, an IMAP server is more involved in the storage and organization of the user’s mail on the server itself. The mail client will connect to it in a similar manner though through port 143. The client will interrogate the server to determine the mail in a given mailbox. The user’s mail may be viewed, deleted or moved to another mail folder. The mail, while remaining on the server, can be organized into a number of subfolders.

The mail server’s administrator might control how much the user is allowed to do. In particular the amount of storage taken up by a users mail may be limited. From a system administrator’s point of view, the simpler it is to maintain a user’s quota, the better.

As the user’s view of the mail is based on the server, his/her connection with the server stays established a lot longer than it would with POP. For a given number of clients a far greater percentage would have active connections if running IMAP as opposed to POP. This is one of the reasons that the protocol takes up more server resources than POP. Another potential load on the server is IMAP’s search command. This allows for an extensive range of search options, these being listed in the RFC. Support for search and other capabilities of the IMAP protocol lead to support for fewer active users on a given server system than if a simple POP system is in use.

The current version of IMAP is IMAP4 and its RFC is RFC 2060.

SMTPThis protocol defines a method of transferring an email message from the originating client to the mailbox of the recipient. As with POP and IMAP, SMTP works through a “well known” TCP port, in this case it is port 25. When a mail item is sent, the system sending the mail will telnet onto port 25 of the system that’s been configured as its SMTP host. The SMTP host will have a set of rules that define where it should send the item so that it may head towards its final destination. One server may send it on to another, which will in turn send it on. Assuming that the email address is correct, the message should eventually arrive at the correct destination mailbox. It might reach a server that determines its destination address is invalid, in which case it might return or might discard the message.

SMTP has been a standard for many years; its RFC is RFC 821.

The use of MIME attachments, such as pictures, video, word processor files, has increased enormously and the flexibility of SMTP has allowed this.


Email clientsThe use of POP or IMAP on a given server (and a server can support both protocols simultaneously) does not dictate a given mail client. Mail client software may have a simple text-based interface, be menu-based or a sophisticated graphical user interface.

Each mail client will have some means of configuring access to its POP or IMAP server in order to receive mail – and an SMTP server to send mail through. The servers need not be the same server or even in the same domain.

As an example of this configuration, Netscape’s Netscape Messenger has the configuration panels shown in Figures 2-4.

Figure 2: Mail Server Properties Configuration Panel

Here the user’s user name at the mail server is kept, and whether the server is POP3 or IMAP. The protocol selection is used to present a protocol specific panel.

The IMAP panel shows some of the flexibility allowed by the protocol.


Figure 3: IMAP Configuration Panel

The POP protocol, offering fewer options, has a simpler configuration panel. The main option, as discussed previously, is whether or not to delete the messages from the server after download.

Figure 4: POP Configuration Panel


Email addressingThere are a number of methods for assigning a user a unique email address. The most commonly used one is to provide a unique id within a given Internet domain. The domain itself must have a unique name within its Internet community, which is handled by the system of allocating domain names. This system also ensures that the domain names can be recognized by other systems on the Internet, allowing routing of mail to the right systems.

A domain, such as dell.com, will be “known” on the Internet, so data for it can be sent to the right systems for processing. If it supports mail, it may have a user ID such as sp_demorgan. Mail sent from outside dell.com would be addressed to [email protected].

A mail server, such as SAMS, can support mail for more than one domain on a given server – assuming the resources required are available: gemgin.com and grempot.com may address the same physical mail server. With SAMS, an administrator may use the direct commands supplied or the Web-based GUI interface.

Ensuring the correctness of mail accounts is one of the tasks associated with maintenance of a mail server.


Section 4Load TestingSystem configurations

Three server configurations were tested, with a total of five user environments. There was a server configuration associated with each of the identified SAMS bundles:

4000 POP users 1500 IMAP or 8000 POP users 3000 IMAP or 15000 POP users

Each of these was running on a single-processor Dell PowerEdge 2450 running Red Hat Linux 6.2. Dual power supplies were installed in all server configurations.

4000 POP users 128 MB RAM 1 x 18GB SCSI Ultra-3, 10K rpm Majority of drive space assigned to /var for mail storage

8000POP / 1500 IMAP users 256 MB RAM 2 x 18GB SCSI Ultra-3, 10K rpm /var allocated as RAID 0 space under linux control

15000POP / 3000 IMAP users

512 MB RAM 4 x 36 GB SCSI Ultra-3, 10K rpm under embedded PERC 3/Si

RAID controller with 64MB cache All drives assigned to RAID 5 array

Test usersFor each of the configurations under test, a domain with the appropriate number of users was created. The SAMS package comes with a command: msadm_bulkadd, which allows a set of user definitions to be read from a file – user names, default passwords, and


a personal quota if one is assigned. During the testing no quota was assigned to allow flexibility in mail delivery.

Load simulationTwo aspects of load simulation have to be decided for a useful study. In addition to the identification and use of tools to accurately simulate a load, it must be decided what the load will be. Determining what accurately reflects a mail server’s load in a particular environment is not a trivial task, with the following issues to be considered:

The amount and type of mailing being received will likely vary between different types of users. The typical home user’s mail usage is quite different from a corporate user. The tests would have to simulate the spread in the type of mail message being received, particularly how it relates to the sizes of the messages.

A user will typically not request the mail server for their received mail uniformly throughout twenty-four hours, nor would the server receive its mail that way. Many users will log on at a given time and retrieve the majority of their day’s mail during one exchange with the mail server.

The number of messages a user receives can vary. Some users will keep their messages on the server while others

will allow them to be discarded. The choice of mail protocol, POP or IMAP, and the features of

the protocol in use, can make a big difference to the processing load on the server.

For a given type of user, what constitutes acceptable performance needs to be identified. For users retrieving mail over a LAN, server delays would be much more obvious than for those using a dial-up connection.

The tool used to run the tests was Mozilla’s mstone tool. This tool was controlled through configuration scripts. In these scripts the nature of the mail environment was described, allowing such things as message number or size to be fixed or vary over a distribution. It allowed control of a number of test clients each generating a load for the server where one described test load is automatically spread across the clients – with each client’s results then being merged with the others to generate a complete performance report. When running each phase of the test, the control system used rsh to initiate the load run on each of the test clients.

Test configurations were created for 4000, 8000 and 15,000 POP users scenario along with the 1500 and 3000 IMAP users. For performance testing these tests were run against the PowerEdge 2450 system configurations after the mail systems had been preloaded into a typical mail state. Distributions of mail were delivered across the user’s mailboxes, and a percentage of those messages were read by the user – while leaving the message on the server, see Figure 5. While the test ran simulating users accessing their mail, additional mail arrived for a number of users.


Figure 5: Test Configuration

One main test system controlled a number of other clients to provide the required load. Prior to the main test runs, each configuration was setup into a mail servers “typical” usage mode, see Figure 6.

Figure 6: Initial State

After this the clients were run to read a large percentage of the mail on the server, leaving it on the server, see Figure 7.


Figure 7: Read Mail Left on the Server

Then the mailboxes were topped off to provide a known amount of unread mail, see Figure 8.

Figure 8: Mailboxes Topped off with Unread Mail

Once in this state, the performance tests can be run. Though the exact number, size and distribution of messages vary per test run, the mail server is always returned to this state for each test run. Typically, an average of fifty messages were in each user’s mailbox.

POP loadsThe POP load is used to simulate a dialup mail user, the configuration for these messages:Size: typically 3K, going up past 48KRecipients: typically one recipient per message, but with a standard

deviation of 1.5mime: 30 % of the messages contain mime-type dataArriving: around five messages arriving during test runPer day: Average of five messages per day, with most messages

retrieved from the server. A read message backlog was created to simulate a typical mailbox.

IMAP loads

IMAP load is used to simulate more of a corporate mail user.

Size: typically 4K going up past 64K


Recipients: typically one recipient per message, but with a standard deviation of 2

mime: 30 % of the messages contain mime-type dataArriving: around fifty messages arriving during test runPer day: Average of fifty messages per day, only 10% deleted

from the server. A read message backlog was created to simulate a typical mailbox.


Section 5System informationSendmail configuration

The main configuration file for sendmail is /etc/sendmail.cf. When using SAMS there should be no need to edit this file directly. When using regular sendmail, this file controls a lot of the system’s behavior. The file is very large and the ruleset it implements can be very complicated, and the file should not be edited without keeping a backup. The file supplied with the mail bundle has been tailored for the size of SAMS installed on that system. The number of users a system supports can alter such parameters as The number of daemons to start

The way mailboxes are stored in a number of configured mailqueues

How the mailboxes are stored – for speed of access there’s not simply a file/directory per mail user.

The maximum number of files a system can have open and the maximum number of inodes used.

PowerThe PowerEdge 2450 systems configured with SAMS have two power supplies allowing a level of redundancy. In an environment that requires a high level of availability, this would be supplied via an uninterruptible power supply (UPS).

RAIDRAID 0With RAID 0, data is striped over two or more disks, splitting any data into smaller parts – one for each disk. Assuming that the system can handle data faster than the drives can, which is typically the case, this allows for faster overall transfer of data. There is no redundancy of data, and the failure of any drive requires rebuilding of the system.

RAID 0 was implemented in the mid level system configuration (1500 IMAP/8000 POP users). No hardware RAID controller was installed on this configuration and the RAID mechanism was through software. Comparing hardware and software RAID implementations entails a price vs. performance comparison.

RAID 5With RAID 5, data is striped over three or more disks along with redundant information that allows for regeneration of lost data. It can


give some of the performance improvements of striping data, assuming handling of the redundant information does not impact that. The redundancy of information will allow for a single drive failure but will reduce the available storage of the drives by 20%. The calculation and writing of the parity information doesn’t allow for the performance to be as high as it would with simple data striping – RAID 0.

If redundancy was required at the data rate of a striped subsystem, a method combining RAID 0 and RAID 1 might be used. The disk array over which the data is striped is completely mirrored on another drive array for redundancy.

BackupSAMS comes with a number of administrative commands. Some of these relate to backup and archive of the mail server’s state. Tape or some other type of locally or remotely attached storage could be used for storage of backups, taking into account any additional system and network load that this will generate. Off peak scheduling could be used to minimize any effect on the running system.

Dell and PowerEdge are trademarks of Dell Computer Corporation. Sendmail is a registered trademark of Sendmail, Inc. Other trademarks and trade names may be used in this document to refer to either the entities claiming the marks and names or their products. Dell disclaims proprietary interest in the marks and names of others.

©Copyright 2001 Dell Computer Corporation. All rights reserved. Reproduction in any manner whatsoever without the express written permission of Dell Computer Corporation is strictly forbidden. For more information contact Dell. Dell cannot be responsible for errors in typography or photography.


Appendices

Appendix AGlossaryWord Definition

POP See popIMAP See imapinode A data structure holding information about files in a Unix file system.

There is an inode for each file and a file is uniquely identified by the file system on which it resides and its inode number on that system. Each inode contains the following information: the device where the inode resides, locking information, mode and type of file, the number of links to the file, the owner's user and group ids, the number of bytes in the file, access and modification times, the time the inode itself was last modified and the addresses of the file's blocks on disk.

IP Internet Protocol is a connectionless protocol used for communication between computers. Frequently used as the base protocol for higher layer protocols such as TCP.

Quota Amount of storage a mail user is allocated. With POP user’s typically downloading their messages, a user’s quota is typically of more importance to an IMAP user.

RFC Request For Comments – standards documents that can be in one of a number of stages of review or be complete and approved. Many uses of the web’s TCP/IP network are defined by RFCs.

SMTP See smtpSocket To distinguish one user of the IP protocol from another they are assigned

a given reference or socket for use.Telnet Protocol that allows remote logon to systemsWell known port

Ports are values that are agreed to by both client and server for use by a particular application. A given application might make temporary use of different ports or might assume a fixed value will be assigned to it. Common, well


1500 IMAP users

Overview of Configuration

Service Hardware Software

incoming SMTP, IMAP Dell PowerEdge 2450 Sendmail Server 1.0

ResultsQoS

Criterion 1500 Users

SMTP: 75% commands < 200 msec PASS(3.41 msec)

SMTP: errors < 0.5% PASS(0.00579 %)

imap: 75% commands < 200 msec PASS(15.2 msec)

imap: 75% login times < 200 msec PASS(6.53 msec)

imap: 75% retrieval times < 500 msec PASS(389 msec)

imap: errors < 0.5% PASS(0.016 %)

Other Metrics

Users 1500

Active users 1500

Messages read per second 5.669

Messages delivered per second 0.472

Mail delivered (k/sec) 16.2

Mail read (k/sec) 146

SMTP connections per second 0.0499

User connections per second 0.278


HardwareIntel 2u

OS Linux Redhat 6.2 (kernel 2.2.14)disks all on software RAID0logging mail.* = -/var/log/maillog (async)parameters file_max = 16384

inode_max = 16384

Memory 256 MBconfiguration 2 x 128 MB DIMMspeed 133MHz ECC

Network integrated 10/100 Mbit Ethernet

Processor 1 Intel Pentium IIIcache 256Kspeed 733MHz

Storage 36 Gcontrollers 1 Ultra SCSI3disks 2 x 18G

Linux software RAID0model Quantum Atlasspeed 10k RPMtype Ultra SCSI3


3000 IMAP users



incoming SMTP,IMAP Dell PowerEdge 2450 Sendmail Server 1.0

ResultsQoS



SMTP: errors < 0.5% PASS(0.00149 %)

imap: 75% commands < 200 msec PASS(17.1 msec)

imap: 75% login times < 200 msec PASS(11.8 msec)

imap: 75% retrieval times < 500 msec PASS(128 msec)

imap: errors < 0.5% PASS(0.227 %)

Other Metrics

Users 3000

Active users 3000




Mail read (k/sec) 302



Average System Utilization

Users 3000

Incoming network traffic (k/s) 70.051 k

Outgoing network traffic (k/s) 323.883 k


% CPU Utilization (user, system) 19, 35

Disk traffic (read, write k/s) 19.865, 19.865

HardwareIntel 2u

OS Linux Redhat 6.2 (kernel 2.2.14)logging mail.* = -/var/log/maillog (async)

file_max = 32768inode_max = 32768

memory 512 MBconfiguration 4 x 128 MB DIMMspeed 133MHz ECC

network integrated 10/100 Mbit Ethernet

processors 1 Intel Pentium IIIcache 256Kspeed 733 MHz

storage 84 GBcontrollers PERC 3/Si (RAID-5) - 128MB cacheDisks 4 x 36GB

Hardware RAID-5model Quantum Atlasspeed 10k RPM, ? ms seek-timetype Ultra3 SCSI

Workload Details

Delivery fluctuation 8 AM - 4 PM = 90%messages per connection 1


4000 POP users



incoming SMTP,POP Dell PowerEdge 2450 Sendmail Server 1.0

ResultsQoS



SMTP: errors < 0.5% PASS(0 %)

pop: 75% commands < 200 msec PASS(0.379 msec)

pop: 75% login times < 200 msec PASS(22.8 msec)

pop: 75% retrieval times < 500 msec PASS(17.5 msec)

pop: errors < 0.5% PASS(0 %)Other Metrics

Users 4000

Active users 400




Mail read (k/sec) 14.7



Average System Utilization

Users 4000


HardwareIntel 2u

OS LinuxRedhat 6.2 (kernel 2.2.14)disks swap, tmp, code, home all on /dev/sdalogging logs on /dev/sda

mail.* = -/var/log/maillog (async)parameters file_max = 8192

inode_max = 8192



processor 1 Intel Pentium IIIcache 256Kspeed 733MHz

storage 18 GBcontrollers 1 Ultra3 SCSIdisks 1 x 18G

model Dell Atlasspeed 10k RPM type Ultra3

Workload Details

Delivery

Message headers ~unif(10, 30)line length 60mime 30 %recipients ~lognormal(1,1.5)size ~lognormal(3k,4.5)

User behavior activity 30 m each 24 hcheck interval ~unif(5m, 8m)connection type latency = 0; bandwidth = 56kdrop rate 0.5%keep 5%


messages per day 5protocol popread messages 0

8000 POP users




ResultsQoS






pop: 75% retrieval times < 500 msec PASS(19.1 msec)

pop: errors < 0.5% PASS(0 %)

Other Metrics

Users 8000

Active users 800








HardwareIntel 2u

OS Linux Redhat 6.2 (kernel 2.2.14)disks all on software RAID0logging mail.* = -/var/log/maillog (async)parameters file_max = 16384

inode_max = 16384



processor 1 Intel Pentium IIIcache 256Kspeed 733MHz

storage 36 Gcontrollers 1 Ultra SCSI3disks 2 x 18G

Linux software RAID0model Quantum Atlasspeed 10k RPMtype Ultra SCSI3

Workload Details

Delivery


User behavior activity 30 m each 24 hcheck interval ~unif(5m, 8m)connection type latency = 0; bandwidth = 56k


drop rate 0.5%keep 5%messages per day 5protocol popread messages 0

15000 POP users




ResultsQoS






pop: 75% retrieval times < 500 msec PASS(21 msec)

pop: errors < 0.5% PASS(0 %)

Other Metrics

Users 15000

Active users 1500








HardwareIntel 2u

OS Linux Redhat 6.2 (kernel 2.2.14)logging mail.* = -/var/log/maillog

(async)parameters file_max = 32768

inode_max = 32768

Memory 512 MBconfiguration 4 x 128 MB DIMMspeed 133MHz ECC

Network integrated 10/100 Mbit Ethernet

Processor 1 Intel Pentium IIIcache 256Kspeed 733 MHz

Storage 110 GBcontrollers PERC 3/Si (RAID-5) - 64MB cachedisks 4 x 36GB

Hardware RAID-5 – down rating storage 20%model Quantum Atlasspeed 10k RPMtype Ultra3 SCSI

Workload Details

Delivery


User behavior activity 30 m each 24 hcheck interval ~unif(5m, 8m)connection type latency = 0; bandwidth = 56kdrop rate 0.5%


keep 5%messages per day 5protocol popread messages 0


Sendmail Contact InformationSendmail, Inc. Sendmail, Inc. delivers the ubiquitous Internet Mail platform for e-communications, applications, and services

Sendmail offers the Mobile Messaging Server for alternative access mechanisms, such as web browsers, mobile phones and wireless devices. The server architecture integrates easily into existing systems. A flexible, template-based user interface makes it easy to customize and brand. Sendmail Mobile Messaging Server supports webmail and WAP.

Website: http://www.sendmail.com/

Address: Sendmail Inc.6425 Christie Ave. 4th FloorEmeryville CA 94608

Telephone 510-594-5400

Fax 510-594-5429


http://www.sendmail.com/

Acknowledgements and CopyrightsDell and PowerEdge are trademarks of Dell Computer Corporation. Netscape, Sendmail Microsoft and Windows are registered trademarks of Microsoft Corporation.

Other trademarks and trade names may be used in this document to refer to either the entities claiming the marks and names or their products. Dell disclaims proprietary interest in the marks and names of others.

©Copyright 2001 Dell Computer Corporation. All rights reserved. Reproduction in any manner whatsoever without the express written permission of Dell Computer Corporation is strictly forbidden. For more information, contact Dell. Dell cannot be responsible for errors in typography or photography.

Information in this document is subject to change without notice.


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