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

Les Mikesell lesmikesell at gmail.com
Sat Mar 27 20:51:40 UTC 2010


Pasi Kärkkäinen wrote:
> On Fri, Mar 26, 2010 at 11:14:18AM -0700, Benjamin Franz wrote:
>> Robert Heller wrote:
>>> I suspect that this is a simular case to what I did: I have a server
>>> with 4 drives.  I have several (small) RAID1 partitions (/boot, /,
>>> /usr, /var, etc.) with 4 mirrors and one large RAID5 with three
>>> partitions and a hot spare (a LVM volumn group, containing /home and
>>> some other partitions). I would guess that the admin with the "8-way
>>> RAID1 for the OS" probably also has a 6 or 8 disk RAID5 or RAID6 for
>>> the bulk of the disks
>> 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..

A hardware controller can fail in ways that kill the kernel too.

-- 
   Les Mikesesll
    lesmikesell at gmail.com


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