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Re: replacing hardware raid with software raid



Andreas Sachs put forth on 5/7/2010 1:50 AM:
> Hi,
> i created a raid-5 array with a LSI MegaRaid 150-6 controller (i used 4 sata drives). Is it possible to use the array without the hardware raid controller with linux software raid/ mdadm?

No, this is not possible.  Did your MegaRAID card die?  If so, you should be
able to purchase a new (I noticed the 150 is past EOL) similar MegaRAID
card, drop it in, enter its BIOS, and have it scan the drives for the RAID
configuration, then save it, and reboot.  (Link to a new in box LSI 150-6 on
Ebay is below)

This is precisely why American Megatrend's RAID division (now a division of
LSI) implemented writing the RAID configuration to the disks themselves
instead of only keeping it in nvram on the card.  This facilitates replacing
a failed controller card without having to restore from tape or other backup
media.  The SCSI AMI MegaRAID cards from the late 1990s had this feature (I
still use one of them, a three channel model 428).  But IIRC back then you
had to replace the failed card with an identical model.  Today, I'm pretty
sure you can use any card in the series which has the same basic BIOS.  It
doesn't have to be the exact BIOS rev, but it has to be the same BIOS code
family IIRC.

Call LSI and tell them what's up.  They should be able to assist you with
getting the correct controller to replace yours and get your array going
again without needing to restore from tape.  If you're just wanting to go to
software RAID after a controller failure, you have no choice but to connect
all the drives to a standard SATA controller, wipe the drives, then
partition them or setup LVM groups, then use mdadm to create a new array.
Then you'll need to restore from tape or other media if you have backups.
If you have no backups, for all practical purposes, your data is lost.  If
you have a few tens of thousands of dollars, I'm sure some of the data
recovery companies could correctly reassemble the data.  But if you have
such financial resources, you'd just buy another LSI card and get back up
and running with little pain or cash outlay.

Here's a new in box LSI 150-6 with cables, identical to your card, on Ebay
for $100 USD Buy It Now.  Sale ends in 5 days.

http://cgi.ebay.com/LSI-MegaRAID-SATA-150-6-RAID-Card-1506064-w-cables-/220600932830?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item335cd719de

Ships to:	United States, Europe, Canada, Australia, Mexico, Japan

I'm assuming you're in Germany.  The card is in Utah, USA.  Might take a few
days to get to you.  Once it does, plug it in, scan the disks for the
previous RAID configuration, save it, boot up, done.  It _should_ be that
simple.

I hope I've been able to help you in one way or another Andreas.

Good luck.

-- 
Stan




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