[CentOS] Re: Problem with dual-booting soft-RAID

[Scott Silva]

Kai Schaetzl spake the following on 6/9/2006 9:31 AM:
> Scott Silva wrote on Thu, 08 Jun 2006 09:29:12 -0700:
> 
>> Pardon my chiming in,
> 
> why should I take offense? Thanks!
> 
>  but this is an adequate way to copy the partition data, 
>> and that is what I used on my software raid systems. Don't forget that the 
>> first part is sfdisk -d, not just sfdisk -.
> 
> Yeah, my typing! Thanks for the confirmation, I'll put it in my basket of 
> valuable snippets.
> 
>>> the pulled out one. I didn't test dropping one of the disks in the middle 
>>> of operation yet. 
>> Don't do that! Don't test by pulling a running disk unless it is in hotplug 
>> capable hardware. Test by using mdadm to remove that drive. 
> 
> That's not a real test ;-) I can test out and learn quite a few things by less 
> harmful ways but I don't know what happens if I rip it out in the middle of 
> operation. After all, that's what's going to happen when it really fails. I did 
> it already once and the drive survived, I'll do it again. I use two old 10 GB 
> drives for testing. I'd regret if I lost one of them since after that I have 
> only *very* old drives for further testing, but it's not a real problem.
> 
>>  
>>> There are two things I realized: 
>>>
>>> 1. disks need to run on different IDE controllers it seems. 
>> That info is in the software raid howto. Some systems are more tolerant than 
>> others, but usually a failed drive will lock the entire channel, so the 
>> primary and the slave would go down.
> 
> Yeah, I didn't read that part of the how-to I guess. On a non-testing machine I 
> wouldn't have put the drives on one channel, anyway, but in this case it was the 
> easiest and fastest option. And I learned something from that :-) Actually, they 
> didn't go down both, but the bootup failed. There was a whole lot of IDE errors 
> on the console, though, after I pulled the cable.
> 
> Kai
> 
Actually, a failed drive will time out and error, but yanking it out while
running could "potentially" create a spike that could theoretically kill the
entire machine. Why don't you at least get a couple of removable ide trays
with keylocks. The run about $10 US each, and turning the key will just kill
the power to the drive, and not do more damage.


-- 

MailScanner is like deodorant...
You hope everybody uses it, and
you notice quickly if they don't!!!!