RAID question

[nate at redhat.com]

On Tue, 15 May 2007, Mark Haney wrote:

> John Nichel wrote:
>> Correct me if I'm wrong, but if I have three 250Gb SATA drives in Raid
>> 5, when I do a df -h, should I be seeing this...
>>
>> Filesystem            Size  Used Avail Use% Mounted on
>> /dev/sda5             914G  1.3G  867G   1% /
>> /dev/sda1              99M   12M   83M  13% /boot
>> none                 1014M     0 1014M   0% /dev/shm
>> /dev/sda2             2.0G   36M  1.9G   2% /tmp
>>
>> If my understanding is correct, I should just be seeing one ~250Gb
>> partition?
>>
>> TIA
>>
>
> Well you shouldn't be seeing one ~250GB drive if you have 3 250GB drives
> in a RAID 5 configuration.  You _should_ see on drive with about ~500GB
> on it as 1/3 of the total drive space is used for parity across all 3
> drives.
>
> So what I'm saying is, I don't have a clue why you're showing ~900GB
> when even with those 3 drives striped you should only see ~750GB.
>

You might want to check your drive sizes... The numbers you're showing 
there indicate you've got 3x 500GB drives in the system setup in a raid 5 
configuration.

-- 
Nate Golnik
 	Red Hat System Administrator
 	1801 Varsity Drive
 	Raleigh, NC 27606