Just getting a quick post in before the end of the month. As you may notice by the picture, a hard drive in my server failed. Luckily this was a backup drive in a LVM which actually wasn’t being used, so there was no data loss. As you can see the damage to the drive is quite large (the most I’ve ever seen in pulling a drive apart). LVM wasn’t too nice to me though. I was quite disappointed that LVM failed to notify me of the drive failure, and/or recognise that there was a problem and mount things in read only, instead LVM continued on it’s merry way, until I found the source of the “clicking” noise in the computer room. Once I worked out which drive it was I had to remove the inode and get LVM to remove it and carry on.
From this, I think there needs to be some improvements for LVM. LVM should have some sort of error detection on drives and send out alert emails. LVM should also do data redundancy. I know LVM isn’t designed to do either, but it seems logical. I want something like a Drobo, but for free running on Linux or FreeBSD. Something where the hard drives can be what ever size they want with redundancy with error reporting. This is just a dream….
I’m also getting into my Uni work, starting two courses, Foundations of Business Computing and Data Communications. Both seem fairly boring so far but I’ll see how it goes.
“Although we’d all like Moore’s Law to continue forever, quantum mechanics imposes some fundamental limits on the computation rate and information capacity of any physical device. In particular, it has been shown that 1 kilogram of matter confined to 1 litre of space can perform at most 1051 operations per second on at most 1031 bits of information.[10] A fully populated 128-bit storage pool would contain 2128 blocks = 2137 bytes = 2140 bits; therefore the minimum mass required to hold the bits would be (2140 bits) / (1031 bits/kg) = 136 billion kg. To operate at the 1031 bits/kg limit, however, the entire mass of the computer must be in the form of pure energy. By E=mc², the rest energy of 136 billion kg is 1.2×1028 J. The mass of the oceans is about 1.4×1021 kg. It takes about 4,000 J to raise the temperature of 1 kg of water by 1 degree Celsius, and thus about 400,000 J to heat 1 kg of water from freezing to boiling. The latent heat of vaporization adds another 2 million J/kg. Thus the energy required to boil the oceans is about 2.4×106 J/kg * 1.4×1021 kg = 3.4×1027 J. Thus, fully populating a 128-bit storage pool would, literally, require more energy than boiling the oceans.”
Taken from wikipedia.