[CentOS] RAID-1 mdadm software raid and kernel crashing on hdd failure

Sat Mar 27 18:01:08 UTC 2010
Benjamin Franz <jfranz at freerun.com>

Pasi Kärkkäinen wrote:
> On Fri, Mar 26, 2010 at 11:14:18AM -0700, Benjamin Franz wrote:
>   
>> Yup. 8 way RAID1 for the OS, 8 way RAID6 for the data. I was hoping when 
>> I setup the 8-way RAID1 for the OS that I would get really good read 
>> speeds since md is supposed to stripe reads from RAID1, but in practice 
>> the RAID6 completely kills it for read performance (~61 MB/sec from the 
>> RAID1 partition vs ~200 MB/sec from the RAID6 partition).
>>
>> In a deeply ironic turn of events, one of the hard drives in that 
>> machine died in a way that freaked the hardware controller driver out 
>> and caused a kernel panic last week.
>>
>>     
>
> I've also seen CentOS 5.3 (or 5.4, not sure) crash when a single sata hdd failed.
> The system was running mdadm RAID-1 mirror, so it shouldn't have been fatal event..
>
> There was kernel oops on the console. too bad I didn't have time to capture it then.
> System was running AHCI SATA on Intel ICH9 controller, with mdadm software raid.
>
> So there's still need for hardware RAID controllers..
>   

I'm not sure that is a good conclusion. The controller *is* a (3ware) 
hardware RAID controller - but the drive failure caused the 3ware driver 
to crash. That I wasn't using the controller in HW RAID mode may not be 
a good indicator that all would have been well if I had been.

-- 
Benjamin Franz