Re: Cannot fix RAID5 failure ...

I might add I had problems with 3 sata drives, mirror with hot swap, turned
out to be a pwr supply problem
- kept on having one of the mirror drives fail, raid rebuilt with hot swap,
only to fall over again some time later -

"Paul" <nospam@xxxxxxxxxx> wrote in message
news:nospam-2204061155510001@xxxxxxxxxxxxxxxx
In article <e2dffn$m63$1@xxxxxxxxxxxxxxxxxxxxxxx>, "John7" <NoSp@xxxxxx>
wrote:

Hi,


I built a system using P5LD2 + 3 SATA drives in RAID5.
For some reason the middle drive failed ( Error occurred(0) ).
Intel RAID rom reports Bootable: no.
The system no longer boots (boot failure message / insert bootable
device
msg )
Odd, RAID5 should remain operational even on 2 drives.
Took out the failing drive, still no boot.
Inserted a new drive, no automatic RAID recovery or manual option to do
so.
M/B manual and Asus site do not mention recovery (great job Asus!).
I'm stuck.


Questions:
1) How can backup data from the 2 valid disks ?
2) How can I trigger a RAID rebuild (is there any) ?


System:
M/B: P4LD2, with Intel Storage Maxtrix ICH7R chipset, bios 0815,
BIOS
settings OK.
RAM: 2x 512MB dual bank Infineon DDR533
HD's: 3x Maxtor 6L160M0, SATA1 160GB (1 in failure)


TIA,
John7

Section 21.1.4 and 21.1.5 on page 88, describe what to do for
RAID 5 problems. It sounds to me like more than one drive has
failed. Or maybe one drive failed, and the reserved sector
info on a second drive is somehow corrupted.

ftp://download.intel.com/support/chipsets/imsm/sb/manual50_oem.pdf

You should realize that there are some classes of faults on these
RAID controllers, that cannot be protected by redundancy. For
example, if all the drives sit inside the same computer
enclosure and share the same power supply, if the +12V output
decides to go to +15V and burn all the disk drives simultaneously,
then it would not matter how many times the data was redundantly
stored. Thus, you should never rely on a RAID as a replacement
system for a backup plan. Backups are still required, and just
as frequently as you were doing them before the RAID was set up.

I'm not experienced enough in file system repair, to know whether
there are any free tools available for inspecting data on a disk.
The first thing I'd want to ascertain, is whether the reserved
sector on each working disk, was still OK. Maybe the Intel RAID
BIOS will tell you whether the two remaining disks are "members"
or not ? I cannot say the interface is too verbose, and leaves
a lot to the imagination. I hope they were clever enough to
use a checksum on the reserved sector data.

What I've recommended to potential RAID users in the past, is
to "practice" with the disks and simulate a failure of an array,
sort of like doing a fire drill. Try this with a minimal amount
of test data on the array, and see if the data survives the
repair procedures, what ever they happen to be.

You don't want to learn how to repair RAID arrays, by working
with your only copy of the data :-(

Another thing you could consider doing, is buy some more
disks, and do a sector by sector copy of the two remaining
good disks. You can then try your experiments on the clone copy
drives, rather than the originals, as you attempt to get your
data back. I learned a lesson the hard way years ago, where
a repair tool destroyed my recoverable data, to my shock and
horror. Now, whenever something bad happens, that is my
first step (copy before trying a repair).

Paul


.

Relevant Pages

  • Re: New computer case - 23 bay
    ... I wouldn't mind going down the two separate cases route, ... o Selling your disks and moving to fewer large capacity disks ... What I think you should consider is RAID 6... ... All SCSI 10K drives. ...
    (uk.comp.homebuilt)
  • Re: A8N SLI Deluxe Question
    ... > Currently the drives are partitioned and my apps are on one partition. ... Someone suggested using RAID 0. ... The media rates for disks are still in the ~70MB/sec range ... the array reports certain errors. ...
    (alt.comp.periphs.mainboard.asus)
  • Re: Exchange Disks
    ... I was looking at using a cheaper alternative with 7,200 RPM Server SATA ... Logs raid 1 mirror ... consider single drives for the OS and or Logs instead of mirrors. ... Is there some sort of rule-of-thumb for setting up disks based on a number ...
    (microsoft.public.exchange.setup)
  • Re: Beginning to think about VMware and SCO 5.0.5
    ... faster 15K drives will provide ... I am now gun shy of SCSI RAID: On 6/12 I was called at 19:50 ... the two RAID1 disks in the primary were down ... and the nightly backup was restored to it. ...
    (comp.unix.sco.misc)
  • Re: New Lightwave Workstation
    ... Id imagine it's better to install a PCI Sata raid controller card rather than run off the motherboard for performance reasons. ... I've always gone with RAID 0 as I don't need the redundency on drives that are used just for rendering. ... | from several disks at once to make up the file. ...
    (comp.graphics.apps.lightwave)