Re: LVM root?
On Thu, Oct 12, 2006 at 10:09:26AM -0400, dtutty@porchlight.ca wrote:
> Board is an Asus M2N-SLI Deluxe (AM2), says it has hardware raid
> (Raid0,raid1, raid0+1, raid 5, and JBOD via the onboard NVIDIA
> MediaShield RAID controller. This sounds like hardware raid to me and
> is configured via the bios menus.
It is fake raid. It is not hardware raid. At best it may have an xor
engine in the chipset that the driver/bios can use to reduce the cpu
load. Marketing people think anything done in the bios makes it
hardware. They would claim a winmodem is entirely a hardware modem too.
> Can you give me either a URL or a thumbnail sketch of how to deal with a
> disk failure if I set it up as you suggest?
If a disk fails, mdadm will send an email about it (you can see it in
/proc/mdstat too). You then shutdown at a convinient time, replace the
broken disk, boot up again and copy the partition table from the working
disk to the new disk (making the still working disk now be the first
disk makes this easier) using something like dd if=/dev/sda of=/dev/sdb
bs=512 count=1, and then reread the partition table with hdparm -z
/dev/sdb, then you ask mdadm to add the new partitions on the new sdb
using mdadm --add /dev/md0 /dev/sdb1; mdadm --add /dev/md1 /dev/sdb2
Then it will resync the mirror, and when done it will be all back to
normal.
With a hardware raid card (not fakeraid), you would be able to just
hotswap the broken drive, and the raid would start resyncing. No user
intervension required.
> You suggest ext3 for the / system. Why would I not just use JFS for
> everything?
Why would you use JFS for anything?
ext3 is solid, reliable, decent performance, and supported by everything
(including the boot loader).
--
Len Sorensen
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