Re: PE2950, RAID 0, failed disk

["Daniel Feenberg" <user=12@nabble.blu.org>]

On Thu, 6 Mar 2008, Ben Holland wrote: 

> Alright, I was going to say something about how RAID 0 just stripes with no 
> parody, a RAID 1 mirrors, so you get a whole drive of redundancy RAID 5 is 
> stripe with parody so you need 3 drives minimum. If you loose a RAID 0 you 
> lost half of your data, you can't recover from it, and chances are you lost 
> all of the other side as well because your file system is totally hosed 
> (though could someone please verify that). RAID 0 I have never seen to be 
> useful. Sorry for the lack of good news. ~Ben 

RAID 0 is striped, so not only do you lose half your data, you lose half 
of EACH FILE, so baring very special circumstances, you will have nothing 
left. However, RAID 0 is still very usefull - in our systems it is 
typically runs at about twice the speed of a single drive, which is nice 
for /tmp and /scratch, where permanent storage is not expected. We have 
applications that write very large intermediate files, and RAID 0 is a 
help. 

Daniel Feenberg 

> 
> On Thu, Mar 6, 2008 at 3:45 PM, Vince Kimball <[hidden email]> wrote: 
> 
>> I believe RAID 0 has no redundancy, so a single drive failure destroys 
>> the volume. 
>> 
>> Scott R. Ehrlich wrote: 
>>> I have a Dell PowerEdge 2950 with PERC 5/i, and 6 disks.  Two disks 
>>> have one logical volume via a hardware RAID 1 and consist of CentOS 5 
>>> 64-bit; the remaining four comprise a logical volume via a hardware 
>>> RAID 0, and is all user data. 
>>> 
>>> One drive on the RAID 0 went bad.   I removed it while the system was 
>>> on, tried a reboot, and the system hangs at RedHat Linux... Starting 
>>> 
>>> I tried to boot from a Fedora 8 CD, which sees the boot drives fine, 
>>> but not the RAID 0 partitions. 
>>> 
>>> Visiting the PERC controller setup claims the RAID 0 volume is 
>>> unavailable, or something similar, though it is defined, with one of 
>>> the disks labelled as missing, since I removed it from the system. 
>>> 
>>> How do I get the partitions on the RAID 0 setup back?   I have some of 
>>> the data, but need the rest, if possible, and the remaining three 
>>> disks appear physically healthy.   I'm also going to work with Dell 
>>> for some answers, and I've done a lot of googling. 
>>> 
>>> Thanks. 
>>> 
>>> Scott 
>>> 
>> 
>> 
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