System administration

Diomidis Spinellis
Department of Management Science and Technology
Athens University of Economics and Business
Athens, Greece
dds@aueb.gr

Client Workstations

Main tasks:

Servers

Important elements:

Rack-mounted servers
Rack-mounted servers

Services

Basic principles:

Debugging Techniques

Basic strategy: Two basic techniques: Tool examples:

The Fix-Once Principle

Namespaces

Namespaces: Naming policies: Management policy:

Disaster Planning and Recovery

Disaster types budget = disaster cost * disaster probability

Actions:

Change Management

Basic principles:

RCS Log Example

RCS file: RCS/ppp.conf,v
Working file: ppp.conf
head: 1.10
branch:
locks: strict
        dds: 1.10
access list:
symbolic names:
keyword substitution: kv
total revisions: 10;    selected revisions: 10
description:
----------------------------
revision 1.10   locked by: dds;
date: 2002/01/21 09:27:15;  author: dds;  state: Exp;  lines: +5 -0
Added CVS pserver rule.
----------------------------
revision 1.9
date: 2001/12/21 07:47:57;  author: dds;  state: Exp;  lines: +3 -3
New phone numbers.
----------------------------
revision 1.8
date: 2001/12/13 07:46:12;  author: dds;  state: Exp;  lines: +6 -5
Disable multilink.
Allow NTP packets.
----------------------------
revision 1.7
date: 2001/11/22 14:44:25;  author: dds;  state: Exp;  lines: +20 -4
Added aueb connection support.
Fixed to work with outgoing ping.
Added missing traceroute roules.
----------------------------
revision 1.6
date: 2001/11/06 19:23:33;  author: dds;  state: Exp;  lines: +16 -6
Blocked SNMP
Contrained application-level data
Fixed cddb.
----------------------------
revision 1.5
date: 2001/11/06 19:22:24;  author: dds;  state: Exp;  lines: +17 -7
Added CDDB, application lelvel data, ...
----------------------------
revision 1.4
date: 2001/02/04 15:04:18;  author: dds;  state: Exp;  lines: +1 -2
Timeout to 2.5 minutes.
----------------------------
revision 1.3
date: 2001/02/03 11:16:06;  author: dds;  state: Exp;  lines: +1 -1
Do not enable DNS, we have our own.
----------------------------
revision 1.2
date: 2001/01/30 23:11:48;  author: dds;  state: Exp;  lines: +168 -11
Added hosts and filters.
----------------------------
revision 1.1
date: 2001/01/20 19:26:15;  author: dds;  state: Exp;
Initial revision
----------------------------
=============================================================================

Manual Change Log Example

Thu Dec 04 14:20:52 EST 2003
To correct wireless dhcp problems download and install fix KB826942

Tue Dec 24 10:16:13 EET 2002
Enable time serving for Windows clients in smb.conf
 time server = True
From Windows execute: net time /set

Thu Dec  5 09:24:38 EET 2002
build kernels
run mergemaster
make installkernel KERNCONF=SPITI
cp /vol/obj/vol/src/sys/OFFICE/kernel /usr/export/boot

Wed Dec  4 15:15:08 EET 2002
In /usr/src run build and install
co /sys/dev/ata/ata-disk.c
rebuild kernel

Mon Dec  2 12:50:17 EET 2002
In /vol/ports/databases/p5-DBD-SQLite/work/DBD-SQLite-0.21
run perl getsqlite.pl 2.7.3 after manually downloading the file)
After that make, make install

Thu Nov 28 10:02:53 EET 2002
pkg_delete newt-0.50.13 dhcpconf-0.7.0
pkg_delete tcl-8.2.3
make install in /vol/ports/databases/sqlite
(also installed tcl-8.3.5)

Sun Nov 17 13:21:29 EET 2002
Run cvsup -g -L 2 -z supfile
Run cvsup -g -L 2 -z ports-supfile
Install ports/p5-DBI
Install ports/p5-DBD-SQLite

Upgrades

Server upgrade procedure:
  1. Existing services
    1. Services offered by the server
    2. Service users
    3. Software offering the services
  2. Ensure each software element works in the new release
  3. Plan testing procedure for each service
  4. Create back-out plan
  5. Choose maintenance interval
  6. Notify users
  7. Run test plan on existing server
  8. Upgrade (with an assistant)
  9. Repeat tests
  10. If tests fail follow back-out plan
  11. Notify customers

Upgrading TAXISnet
Upgrading TAXISnet

Centralising and Decentralising

We often must decide for or against central or distributed approaches. The following facts can aid our decision: Centralised management candidates:

The Helpdesk Service

To plan a helpdesk service you need to consider: An important element of a helpdesk service is an information system that provides the following functionality:

Example of a Problem Entry Form (Bugzilla)

Product Browser
Component

The area where the problem occurs. To pick the right component, you could use the same one as similar bugs you found in your search, or read the full list of component descriptions if you need more help.

Select a component to see its description here.
Hardware Platform
Operating System
Build Identifier
(User Agent)

This is the line beginning "Mozilla/5.0" in Help | About Mozilla. It identifies exactly the version of Mozilla you were using. If you are using the problem copy of Mozilla, this will be filled in correctly for you already. If Mozilla won't start, just enter the URL of the directory you downloaded it from.

URL

URL that demonstrates the problem you are seeing (optional.) IMPORTANT: If you are filing a bug about a broken web page, you need to read the Mozilla Web Developer FAQ, which explains how we handle old or badly-coded web pages.

Summary

A sentence which summarises the problem. Please be descriptive and use lots of keywords.

Bad example: mail crashed
Good example: crash if I close the mail window while checking for new POP mail

Details

Expand on the Summary. Please be as specific as possible about what is wrong.

Bad example: This page looks wrong in Mozilla. Other browsers display it correctly. You suck!
Good example: In the page at http://www.foo.com/, text in the first column should be fully justified -- text should be aligned with both the left and right margins. In Mozilla, the text is only left-justified.

Reproducibility

How often can you reproduce the problem?

Steps to Reproduce

Describe how to reproduce the problem, step by step. Include any special setup steps.

Actual Results

What happened after you performed the steps above?

Expected Results

What should Mozilla have done instead?

Additional Information

Add any additional information you feel may be relevant to this bug, such as the theme you were using (does the bug still occur with the default theme?), a Talkback crash ID, or special information about your computer's configuration. Any information longer than a few lines, such as a stack trace or HTML testcase, should be added using the "Create a new Attachment" link on the bug, after it is filed.

If you are reporting a crash, note the module in which Mozilla crashed (e.g., Application Violation in gkhtml.dll). On Macintosh, if you have MacsBug, attach the results of the how and sc commands.

Security

Check this box if this is a security problem that needs to be kept confidential (see the mozilla.org security policy for more details).

Severity

How serious the problem is. Also, if your bug is a request for a new feature or enhancement, say so here.

Search Form

Search form

Search Results

Bug #
Dupe
Count
Change in last
7 day(s)
Component
Severity
Op Sys
Target
Milestone
Summary
22274
126
0
Layout
normal
All
---
[INLINE] Too much space (for descenders) under image elements
20618
98
0
Browser-General
major
Windows 98
---
Mousewheel doesn't work with some driver/Win32 OS combinations (scroll, scrolling)
195600
88
0
Installer
critical
Windows 2000
---
browser crashes on startup after install and after xpi install. Installation of 1.4 fails
25537
83
0
Layout
enhancement
All
---
alt text is not displayed as a tooltip
38488
71
0
Networking: HTTP
major
All
---
Proxy:junkbuster is broken - use http/1.0 to get arround this
28586
62
0
Embedding: Docshell
enhancement
All
Future
meta bug - show error pages instead of dialogs for network errors (placeholder page in the content area) (http error pages)
11459
62
0
Preferences
normal
All
---
need option for mailto: to launch external mail app or open a webmail url
105547
62
0
Tabbed Browser
normal
All
---
Windows open in new window instead of tabs (target=<nonexistant_frame>)
69938
59
0
File Handling
critical
All
Future
Downloads are stored in $TMPDIR|$TMP|$TEMP|/tmp first and moved to the selected path after the download finishes
94035
58
1
Plug-ins
enhancement
All
Future
Allow blocking of any media type (flash, plug-in, applet, etc.) by site (like cookies and images)
193638
58
0
Preferences: Backend
normal
All
---
corrupt or lost pref.js / startup configuration error
167663
55
0
XP Apps
critical
MacOS X
mozilla1.0.2
[OS X]window disappears when clicking the maximize button (green +)
104532
53
1
Tabbed Browser
normal
All
---
Status bar ticker fails to update when tabs switched.

Customer Support

The steps:
  1. Greeting
  2. Learn about the problem
  3. Reproduce the problem and agree with the customer
  4. Try the problem
  5. Locate problem resolution proposals
  6. Select solution
  7. Execute solution
  8. Verify solution
  9. Agree with customer that problem has been solved
The problem life cycle
The problem life cycle

Organising the Data Centre

Data center />
Data center

Seen outside a data centre:
                        ACHTUNG!!!

Das machine is nicht fur gefingerpoken und mittengrabben.  Ist easy
schnappen der springenwerk, blowenfusen und corkenpoppen mit
spitzensparken.  Ist nicht fur gewerken by das dummkopfen.  Das
rubbernecken sightseeren keepen hands in das pockets.  Relaxen und
vatch das blinkenlights!!!

Network Management

Possible network topologies:

Intermediate distribution frame

main distribution frame (MDF
In large buildings a main distribution frame (MDF), often located at the data centre, acts as a central hub.

Basic principles:

Distribution frame
Distribution frame. On the bottom one can see the UPS units.

Email Services

Functional units Basic operational principles:

Backups

Backup copies are required when: To optimise the backup process we can distinguish the following types of backup: Every level contains differences from previous level.

Ensure that:

References

Discussion Topics

  1. Outline the services offered by your organisation's (or the University's) data centre
  2. Provide an example where the symptom, rather than the cause is corrected
  3. Describe the naming policy and the management procedures for the .gr domain