CERC ATA100/4CH on Linux (Was: What RAID in PE1655MC blades?)

Seth Mos knuffie at xs4all.nl
Wed Apr 10 11:39:00 CDT 2002


On Wed, 10 Apr 2002, Jerker Nyberg wrote:

> On Wed, 10 Apr 2002, jason andrade wrote:
> 
> > i'd love to buy a bunch of 350s if i could do hardware raid1 on them -
> > though i'm contemplating whether linux's software raid1 might be
> > acceptable.  i can't quite see how it'd work if the primary drive dies
> > though unlike hardware raid..
> 
> It is quite easy to find out. Install Red Hat 7.2 with raid1 over two
> IDE-drives. Power-down the first IDE-drive. Keep on running. :-)
> 
> Of course, replacing the failed drive is difficult without rebooting the
> machine. (Maybe need to boot the kernel from floppy in order not to get
> "no operating system" or something form the BIOS?)

Normally lilo installs on both drives and the bios will boot from the 1st
bootable IDE drive. Well... atleast that is what most asus mainboards do.
They silently fall back to the next bootable IDE drive.

> There may of course be some more difficult drive failures that require
> hardware raid, but I havn't yet run into them... 

Like?

> In my experience, the major problem with IDE-drives running with software
> raid1 is that they seem to drop out of the array even when they should be
> ok... I'm only using SCSI hotswap software-raid now.

Or they are silently generating errors and using there recovery method to
replace the damaged sectors. Sometimes eventhough the error is recovered
from by the drive the linux software raid takes notice.

Cheers





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