The thing that most impresses me about this process is that the copying is taking about %5 (on average) CPU for the actual cp process, and barely any time at all for the md1_raid5 and kjournald processes. So doing RAID5 in software certainly doesn't require a huge grunty CPU (this is an Athlon 2400, yes, but it hasn't even broken into a sweat yet). This'd all be possible on a VIA EPIA motherboard... And, once it's finished, I'll have a root volume that can stand a complete drive failure before it starts worrying, and when it does I'll simply add a new drive, create a new PV, add it to the VG, create a new LV for the new drive, add the drive as a new hot spare, and remove the faulty LV; all at my leisure.
The fact that I can understand all this and think it 'relatively simple' gives me a small measure of pride. One of the few things I would thank EDS for in the time I spent there was sending me on the Veritas volume management training course. LVM is still pretty easy to get a grip on without that kind of training, but it's still made things a little easier.
(Educated readers would be asking why I specified -p ra rather than using its default, ls (or, in other words - why use the parity write policy of right asymmetric rather than left symmetric?) There's no particularly good reason. Firstly, I want asymmetric rather than symmetric to spread the parity load across disks, as is consistent with RAID5. Secondly, when I see an option like this I tend to want to choose the non-default option because, if all options are tested equally but most people use the default, then if a failure mode comes up then it's more likely to be found in the default case, and that may not affect the non-default case. It's a version of the "all your eggs in one basket" argument. I don't give it much weight.)
And all of this over an command line, through SSH, to home. I love technology (when it works...)
What I thought was ironic was that said Perl detractor has been working on some cool stuff - Microsoft's PDF-alternative format, and some other stuff in KDE that was more than nominally neat but has now slipped off the bottom of my stack. Now, I know that I tend to spend a lot of time telling people about my opinions on stuff - this blog may be a prime example. I do also try my best (I think) to be interested in other people's projects and interests, so I don't think I present a one-sided write-only approach. (As always, please email me at email@example.com, anonymously if you want, if you want to correct me on this :-) It's a little depressing, though, when no-one wants to talk about the topic of the night but wants their own ideas to be heard and applauded.
(Not that I hold anything against the person in question. I just wanted to talk gnarly Perl stuff, that's all :-)
All posts licensed under the CC-BY-NC license. Author Paul Wayper.