I expect that something is wrong with the process you used to copy the image to the flash. Could you enlighten me as to your procedure?

–JATF

I had iMedia Linux installed on my alix box, but was looking for something with better package management, etc. I flashed up my 2gb card with alix-centos-5.5-2gcf, but it won’t boot. I think I don’t have the right bootloader. The last bit that shows up before boot fails is:

01F0 Master 045A InnoDisk Corp. – iCF4000 2GB
Phys C/H/S 4063/16/63 Log C/H/S 1015/64/63
Loading iMedia …Error 17

Do I need to update the bootloader with GRUB or something like that? I followed the general directions for dd’ing the image, but that was apparently not enough.
Thanks in advance for your help!
-Casten

Thanks for the information! I don’t have any Alix with the vga, so I’m unable to test. I’ll put your comment into the main post.

–JATF

Interesting. I’m not sure why you would need to delete the cache, but it’s probably a good idea for me to remove the cache from future images anyway. Thanks for the heads up.

The backup you suggest is the easiest and most complete way to do a backup of the compact flash. It will also take the longest time, since it is copying empty space as well as data. There are a variety of other, more efficient ways of doing it (just like any linux system), but the command you specify is certainly the simplest. I would suggest that you compress the image after the fact with bzip [ bzip /tmp/my-wifi-alix-centos.cf ] or during the process [ dd if=/dev/hda | bzip > /tmp/my-wifi-alix-centos.cf.bzip ] which will make the image much smaller, especially with all that empty space.

–JATF

I don’t recommend disabling logging, especially in a production environment. Doing a post mortem off a failure of a production device is critical, and modern flash drives are very robust. Each cell can be written to millions of times, and the flash disk hardware ensures that the lifespan of the device is maximized by using write leveling (prevents you from writing to the same spot over and over, even if you try), and error correction and lockout (verifys each block after write and locks out blocks as they fail). What I would do is this: on your test device, verify the average daily log file size in blocks. Calculate how many blocks per year are expected to be written. Divide by 1,000,000 writes. That’s how many blocks you would ‘consume’ (as in wear out completely) in one year. Multiply by the lifespan of the device (say 10 years), and then double that amount.

You will notice that unless your logs are VERY large, the results are small enough as to be meaningless because there wouldn’t be enough of them to store the data in the first place. That’s because flash drives are very, very robust and you shouldn’t worry about it unless you are really pushing the limits.

The benefits of having system logs far outweigh the maintenance headache they may cause.

Cheers.

–JATF

- I would add I had to remove yum cache to have it working properly to be able to install the wap_supplicant package (something like rm -rf /var/cache/yum/…

- Now just a question: to create an image (I’d like to backup my CF) is it enough to do: dd if=/dev/hda of=/tmp/my-wifi-alix-centos.cf ?

Regards,
PhR.

I’m going to be using this in a production environment, so I want to maximize my CF card lifespan.

Thanks, and thanks for this image!

PS: I installed to a 4gb card and successfully added a pv and extended the lvm group with no problems.

I had considered each of those items when creating the image. Our requirements are somewhat different. If you are maintaining an image for your work you have tight control over who does what to the unit. Releasing the image to the public, I must consider that novice builders will use the image to make a variety of appliances and I wanted to make it as bulletproof as possible. Plus, let’s be honest: I’m lazy, and the closer I can keep it to a stock Centos install, the less likely I’ll be to have people asking questions because something isn’t where they expect it to be.

I selected ext3 because the Alix has no backup power facilities, and if someone uses it for a SOHO router or firewall it is very likely that a user will unplug the unit at some point to reset the network, or a power outage will cause the unit to be reset mid-process. Ext3 should automatically recover from this, but ext2, without the journal, has a high probability of causing the file system to stall when the unit is booted next, requiring a console hook-up to complete the fsck cycle. For most appliances, this would be considered unacceptable. Advanced users will know that they can turn the journal off with tune2fs, but the novice builder will be better off with this safeguard. Modern flash cartridges use write leveling and bad-block exclusion and each block is good for tens of millions of writes, so even with the journal they should last years and years as an appliance. Also, the use of tmpfs should limit the flash-based writes to the /tmp directory. The Alix’s processor and memory specifications restrict it from being an effective server for write-intensive services like a major database or web server anyway, so I think there is very little risk there. If someone is looking to use the Alix in a write-intensive environment (say, as an IDS logger) they are most likely an advanced user and should solder an IDE header in place and put in a 1.8″ or 2.5″ hard disk instead of flash. They’ll have much more space and much better long-term performance since the flash write performance will degrade over time.

As for the space savings, I considered that the price of flash having dropped like a stone the last few years and the small level of space savings compared to the 2GB image size did not warrant the inconvenience of having no documentation or basic services at the builder’s disposal. Again, the advanced user can remove any package they wish with a variety of tools, but the novice may not know exactly how to get that basic functionality back, or at the very least might have to waste many hours trying to figure it out. I run my servers with 4GB cards and 8 – 64GB cards are available for someone who might need vast amounts of space in a small package, or who want to extend the run-time of the unit.

I thought about having more descriptive LVM names, but most tutorials online use the standard names so I just stuck with them. Again: Keep it simple so I can be lazy.

Thanks for the input. I’m not attempting to be argumentative and hopefully I’m not letting my ego get the best of me. I just wanted to let you know that I did think about each of the points you brought up. I might have made bad decisions for some people, but I hope that they are good decisions for most people.

It’s nice to know I have a bedfellow out there working the Alix/Centos images. Do you have many of the platforms? I have only the 6e2. I’ve been swamped with our youngest son finishing High School and my wife starting a new job so I haven’t done an upgrade to 5.6 yet. I’ll be on travel for two weeks and I plan to bring one with me to work on in the hotel. Who knows – maybe they’ll release 6 in the mean time and I can get them both done at once!

Cheers

–JATF

i work on the same project regarding centos and alix in our company and have made some images by my self.
I would like to share my experience with you: it would be better to use a ext2 filesystem or deactivate the journaling in ext3 so write operations are as minmal as possible. also a minimal installation of centos would be nice, this way some of the stuff you have deactivated, kudzu, iptables…, wouldn’t be installed, you just can uncheck all boxes in the extended package selector at the setup screen, you also would save much diskspace because all documentations are not installed this way….

some meaningful names for the volume groups and logical volumes in LVM would nice, but that could be just my petty-minded brain

kind regards.