Reinstalling Red Hat 6.2 Linux - 6/11/00

Spending time on both UNIX like systems working with site searching caused me to realize that I had both backup and space issues I had to deal with. When I started with both the Red Hat and OpenBSD systems they were nothing more than a CDROM install. I'd been pretty careful about documenting my install choices so should be able to repeat the install of either system in an hour or so. Even when I started working with the GeodSoft.com web sites, these were copies from other systems so by definition pre backed up. I had not done anything about a system backups on either system which is very unlike me. I have automated nightly tape backup of my NT workstation. In 17 years, the worst data loss I suffered on a personal PC was about 4 hours when an editor hiccuped and saved a 0 length file. My most recent backup then was just about 4 hours old.

At this point I had a few open source products installed on the Red Hat system. The Apache setup was increasingly customized and similar to but not identical to the OpenBSD Apache setup. The graphics and search script were on my NT workstation but the Swish-e configuration and customized search form existed only on the Linux machine. I'd started setting up custom crontab entries and written a couple of system management scripts. If I suddenly lost the Linux machine hard disk, it would be a major effort to recreate this work.

Partitioning Choices

When I tried building a tar that captured everything that I had put on or changed on the Linux system since the install, I ran out of space in my /home file system. While that was in part a result of an accumulation of junk that I didn't really need and hadn't been managing, df made it clear that sooner or later I was going to need more disk space in both /home and /var.

With the benefit of hindsight, I realized I'd made some really bad partitioning choices when I did the Red Hat install. I'd made everything larger than suggested but left nearly 70% of the disk un partitioned. I'd let my experience with AIX's really sophisticated disk management, fool me into thinking that I'd be able to add space to file systems anytime I wanted. My knowledge of Intel PC architecture and disk partitions as well as the Red Hat documentation should have told me this would not be the case.

As I studied the options, it became increasingly clear that 1 file system = 1 disk partition. I considered trying to tar /var, /home and /usr with the intent of recreating them in larger partitions and then restoring from the tars. Since /var and /usr were always busy this didn't look practical. I thought about creating one large partition with all the remaining disk space and using symbolic links to point to an area in this new file system whenever more space was needed. I ruled that out because it would create a rat's nest of symbolic links that would make backups and restores much more difficult.

I also thought about creating new file systems with mount points inside of those that needed more space. Though I had a fair idea of which file systems needed more space, I still don't know the system well enough to predict which directories will need space. Without this knowledge creating the maximum number of little partitions won't be very flexible and creating only a couple of large partitions will create a different rat's nest of symbolic links.

After considering all the options, I decided that the best long term solution was to start over and reinstall Red Hat Linux with a few relatively large partitions, sized as they were likely to be needed. I briefly considered one huge / partition which would provide the greatest flexibility but also seems less secure and more difficult to recover. Before I could reinstall the system, I had to create tars of all the changes that had been made to the Linux system since it was installed. These were ftp'd to the NT system and burned onto a CDROM.

Putting Things in the Right Places

Besides doing a better job of partitioning the hard disk, reinstalling gave me an opportunity to do other things better. When you delete partitions on a system you've been using , you can't help but worry if you've backup up everything you want. If you haven't, it's gone forever. My concern was heightened by the fact that I wasn't completely sure what all the changes were that I made to the system.

This time I was going to be very systematic. Everything that I added to the system was going to go into /usr/local, /var/local or /home. If I can stick to this, it will make it much easier to reinstall in the future if that's necessary or to recover from a system failure.

Video Problems

The install seemed to go fine up to the monitor and video selection. The install correctly detected both the monitor and video card but I got no video output when I tested the default configuration. In fact I almost ruined my monitor because there was a definite burning odor following the tests. By trial and error I found settings that worked and several days latter the monitor is still working so hopefully there's no permanent damage.

There is another video problem that's persisted through all my Red Hat 6.1 and 6.2 installs. Under the X Window system, about once a minute a back tick ("`") appears in any modifiable field that has the focus. This can be dialog box input fields, text editors, command line in console sessions or even standard output. If the current window has no area that can accept typed characters or standard output, a beep occurs exactly as if I press a key. This is highly annoying as I have to watch everything as it's typed so these stray characters can be deleted as they appear. When I switch to another computer there may be a whole line of these characters when I return to the Linux PC.

Mouse Problem

Following the install when I started X windows, every time I moved the mouse, the mouse cursor jumped to the upper right corner making it completely useless. I have two mice near each other. A Microsoft Intellimouse is directly connected to my NT workstation and an older Microsoft serial mouse is connected to an 8 port KVM sharing box that all my other computers connect to. I mistakenly told the Red Hat install that I had an Intellimouse on the system being installed. I eventually found the /etc/sysconfig/mouse file and tried editing that based on the listed mouse types in the boot.log error messages. I tried erasing that file in the hopes that the system would detect the real mouse or give me an option to change/select a mouse. I tried several "upgrades" via the Red Hat install program both with and without an /etc/sysconfig/mouse file present. Nothing would make the Install/Upgrade program write a new correct mouse file. Finally after searching the Red Hat site, one line at the bottom of one of the pages that showed the mouse install procedure mentioned a mouseconfig program. That immediately fixed the problem but it took me almost a day to find that. I also subsequently realized that "man -k mouse" would list mouseconfig in the middle of two pages of output.

What gets me is the Red Hat install program. Even though it doesn't normally update hardware when doing an "upgrade", it seems obvious that when it detects a mouse and the system has no mouse definintion it should update it or at least give the user that option. I never tried a full install because it just seems nuts to completely reinstall a system to change a mouse type.

Apache Problem

Also following the install, Apache was no longer running, even though it had come up automatically following previous installs. At this point I can't remember if that was before or after restoring the customized Apache configuration file. When I tried starting Apache from the command line, I got an error message that it "cannot determine local host name. Use the ServerName directive to set it manually." After doing that I got another error message "Failed to resolve server name for . . ." I turned my attentions to other things but noticed during the boot process that apparently httpd was successfully starting and stopping. A web browser check confirmed that Apache was running and both web sites were available. A check of the boot.log showed that Apache continues to display the second error message but works anyhow.

Why did I never see these errors before and see them now? I've never had a DNS server available which the full message suggests is necessary. I only did two things differently related to networking. I changed the host name but without DNS it's hard to see how "redhat" should be any more or less meaningful than "gds-l1". I also defined the alias IP address for the GeodSoft.com site in linuxconf rather than the Gnome control panel but the net result seems to be exactly the same network configuration files. Since it seems to be working fine, I'll ignore the Apache error message until I have an SDSL line and a proper DNS setup. Then I try dealing with it if it's still an issue.

Update 08/22/00

I was reviewing this page and the Apache error messages described in the preceding paragraphs. It does appear that I fixed the problem as the error messages are no longer appearing in the boot logs; I don't remember when or how. I think the cause of the error message was that along with the Red Hat Linux upgrade came a small Apache upgrade. I'm not sure exactly which version of Apache, Red Hat 6.1 came with but it should have been 1.3.9 or slightly earlier. Red Hat 6.2 includes 1.3.12. I think the new error message was due to a slightly different version of Apache that's including some checks that were not present in earlier versions.

System Backup

As soon as I had everything back on the system, often in new locations and everything working that I had been using previously, I decided to focus on backups. I don't have tape drives on any system but my NT workstation and don't want to spend the money that they and sufficient media would cost. Since, at least for the foreseeable future, now that the full drive is available and I did not restore the junk that had been accumulating, I have lots of excess disk capacity. My plan is to backup only what I add to or change on each system after the install.

On the Linux system I've created two scripts. One runs from cron automatically each night. It backs up every file on the system that has been modified since the system was installed. Directories that are recreated during an install or are created and managed by the system are specifically excluded. This includes /boot, /proc, /var/cache, /var/lock, /var/run, etc. The /var/local/backup directory which stores all the backups is also excluded. A text log file of all the files included in each backup .tar file is also created. At the end of the backup, both the .tar and .log files are ftp'd to another system. It's my plan to keep backups for each system on one other system. From time to time I'll copy the backups or at least a subset of them to a writable CDROM and then erase those on hard disks.

The other backup script identifies and backups up to a tar file, all the products that have been installed independently of the system install. Since many of these will have modification dates prior to the system install date, they would not be backed up by the daily backup script. I'll run this script each time after I add new software to the system.

With these backups, recovery from a system loss should be straight forward. Start with a full Red Hat install, using my notes from the last install to get back to the basic system. Restore from the occasional post install backup then restore from most recent daily backup up.

Top of Page - Site Map

Copyright © 2000 - 2014 by George Shaffer. This material may be distributed only subject to the terms and conditions set forth in https://geodsoft.com/terms.htm (or https://geodsoft.com/cgi-bin/terms.pl). These terms are subject to change. Distribution is subject to the current terms, or at the choice of the distributor, those in an earlier, digitally signed electronic copy of https://geodsoft.com/terms.htm (or cgi-bin/terms.pl) from the time of the distribution. Distribution of substantively modified versions of GeodSoft content is prohibited without the explicit written permission of George Shaffer. Distribution of the work or derivatives of the work, in whole or in part, for commercial purposes is prohibited unless prior written permission is obtained from George Shaffer. Distribution in accordance with these terms, for unrestricted and uncompensated public access, non profit, or internal company use is allowed.