I have upgraded my dual celeron server to Mandrake 9 early this morning in a twisted way. It did not turn out to be a smooth upgrade, and meanwhile I am still trying to iron out the things that are broken.
Last night (or 1am this morning, to be more precise) I was working on burning the Sunday sermons to my old 6x CD recorder. However, I experienced 3 buffer underrun with the 2 CD I am trying to burn. At the end, I need to burn the CDs using 1x speed, which took me more than 40 minutes for write last Sunday's talk by Robin Gan, to stop myself getting more coasters. I am puzzled - it has never been the case, and I can always burn CDs using full speed previously without buffer underrun. Moreover, I noticed that whenever there's a disk activity, the buffer metre of cdrecord starts to drop, and then finally reached 0% and ejected the disc. Why is it happening to me!
I was supposed to work on the program outline for the coming Saturday's event, but I decided that I'll diagnose the problem. Because I suspected it is the disk's problem, I thought I'll give hdparm a try. After a few minutes of playing around, I found my /home partition, which is parked on a Maxtor 30Gb drive on a CMD648 DMA66 chip, can only do 1.6Mb/sec transfer from the drive! This is insane which explains the poor performance I'm getting from my all powerful dual 400Mhz box recently (if there is any). 1.6Mb/sec - that's about the same speed as the old 10BASE2 ethernet, which is very slow. No wonder it cannot sustain 6x write which requires 900kb/sec feed. Now the question is - why is it so slow? I've used hdparm to check the DMA setting - it is turned on to use UDMA mode 4. However, looking at the interrupt settings in /proc/interrupts it shows CMD648 (IDE2 IDE3) is using IRQ19, which is kind of strange (due to my lack of hardware knowledge, probably).
Then I thought, "maybe I can use this opportunity to upgrade to Mandrake 9, and see whether the latest and greatest version of software can help me". I had downloaded Mandrake 9 for quite a while already, and had installed it on my notebook and work machines. However, I have not had a chance to make a upgrade on my home Mandrake 8.2 box. Alright, shutting down the box, reboot, pop the CD in, and wait for the installation to boot. I went straight to the text mode, selected automatic update, and soon it started copying files across. After 3 CD's, then it reboots to start the upgraded Mandrake box for the first time.
It boots okay, went straight into the getty. However, it did not really resolve my hard drive problem, and it is still reading at 1.6Mb/sec :( Moreover, due to some incompatibility between Mandrake 8.2 and Mandrake 9, some services do not work anymore. For example, PHP PEAR is now sitting in a different directory. Postfix's symbolic links are all wrong, etc. By the time I've finished checking and fixing, it is already 4:00am. D'oh. Need to sleep.
I still have not been able to find out the exact problem of the hard drive. It is a relative new drive - circa April 2000. Well, it is relative new because the other two drives in the box (both Quantum) are 4-5 years old. It might be the interface card, which I will swap some bits and pieces to test out the problem. Dodgy PC hardware... Update: I think it is the Maxtor's problem - I change the channel of the drive, but it is still performing miserably. Now I know which drive I will not get... Just got Vivian's approval to get a new drive. Hmm. 80Gb Seagate Barracuda is selling cheap at the moment :)