Best of Tech Support

Various

Issue #105, January 2003

Our experts answer your technical questions.

Bulletproof Backup /boot?

I have a number of remote Linux workstations that I need to ensure are always available to me remotely. I am looking to set up these systems in a TiVo-like fashion, whereby each machine would have two boot partitions and two root partitions. The goal is to be able to perform maintenance operations on the primary-use partitions via a secondary-use boot and root partition. I require only basic functionality while in the secondary partition, namely e2fsprogs and a DHCP-networked sshd. I intend to use LILO or Grub and an init6 to switch between the setups. Assuming that console access is never an option, what is the most bulletproof way to lay out the partition tables and configuration for something like this?

—Marc Lavergne, mlavergne@cfl.rr.com

You really don't need a second partition to boot in to for updates. RPMs allow updates on the fly. In fact, the only reason you need to reboot is to run an upgraded kernel. That being said, the ping-pong methodology you discuss is always a good idea if you mess something up during an upgrade. AFAIK, LILO and Grub do not support a feature that allows you to boot an alternate partition if the previous boot failed. You would probably need to write some code to accomplish this. This solution, however, will not fix system hangups or hard crashes. Truly remote systems usually need some hardware console support.

—Christopher Wingert, cwingert@cwingert.qualcomm.com

It sounds as though you need a solution that doesn't require the remote user's assistance. Otherwise, I would recommend a bootable CD; some, like Gentoo, even include SSH functionality.

—Chad Robinson, crobinson@rfgonline.com

There's not really one partition table setup that would be better than the others. The only thing that's a tad more bulletproof is to use only four partitions so you don't use extended partitions. That way, your entire partition table is in the master boot record of your disk and not spread out around your disk in a linked list. That said, it won't really make a huge difference, unless very bad things happen to your disk.

—Marc Merlin, marc_bts@google.com

Linux Driver for Belkin Wireless Card?

I recently installed a wireless PCI network card, but the company, Belkin, doesn't supply a Linux driver. I searched around and found the Linux-WLAN driver. I tried to install it, but when I was making the driver (make all), I received several error messages, and it wouldn't compile.

—Matt Jacobs, mjacobs519@hotmail.com

If you want to get on the Net fast, the good news is Belkin seems to be using the common Prism/2 chipset, like many other vendors. Tim Miller has put together an RPM for Red Hat 7.3 and 8.0 to support Prism/2-based cards (prism2.unixguru.raleigh.nc.us). If you want to build drivers from source, either because you want a custom kernel or want to learn how it's done, work through the Kernel HOWTO (www.tldp.org/HOWTO/Kernel-HOWTO.html). Make sure you have everything needed to build a “stock” kernel first.

—Don Marti, info@linuxjournal.com

CD Install Hangs

I tried a number of times, by booting from the CD-ROM, to install Red Hat 7.3 in a NEC P150 machine. But I keep getting hung up half-way through the installation.

—Leong Y C, leongyc@tp.edu.sg

Try changing the use of DMA on the BIOS for your CD-ROM drive unit. On some machines the CD drive hangs if this is set incorrectly. This can happen not only with Linux, but with any operating system and with applications on CD.

—Felipe E. Barousse Boué, fbarousse@piensa.com

You can try three things: 1) disable autoprobing of hardware (boot with noprobe); 2) try an install in text mode; and 3) if you purchased it, talk to Red Hat for installation support.

—Marc Merlin, marc_bts@google.com

Making Snort, MySQL and ACID Work Together

Does anybody know where I can find a one-stop shop that shows in-depth how to install Snort on a system with MySQL and ACID? I have been trying this for three weeks, but the ACID console will not log the events.

—Colin Slevin, Colslev@transwareplc.com

You don't mention whether entries are being logged via other means. Snort typically will log to a number of channels in its default installation. If you aren't getting entries logged at all, the problem is likely elsewhere. Otherwise, edit your snort.conf file. A number of logging examples are there, and you should be able to mimic one that suits your needs. Snort has a mailing list whose users are very supportive. You can subscribe by visiting www.snort.org/lists.html. I recommend submitting your question there. Supply your exact installation procedure so somebody can help you more thoroughly.

—Chad Robinson, crobinson@rfgonline.com

Sharing a Windows Box's Printer

How do I use a shared printer connected to a Windows 2000 Pro PC? I have Mandrake 8.2.

—Sam Dorrough, dorroughs@microdyne.com

Check that the printer is shared from the Windows box and that you have Samba installed on the Linux box. Then run printtool on the Linux box to set up access to the printer.

—Christopher Wingert, cwingert@cwingert.qualcomm.com

It is best to share the printer with a Windows box that has a name of eight characters or less. I have had problems with longer names of shared devices. Documentation on Samba and printers can be found at: us1.samba.org/samba/docs/Samba-HOWTO-Collection.html.

—Felipe E. Barousse Boué, fbarousse@piensa.com