Re: Direct disk access on IBM Server

[David Brown <david@westcontrol.com>]

On 19/04/2011 17:41, Mathias Burén wrote:
> On 19 April 2011 16:12, David Brown<david@westcontrol.com>  wrote:
>> On 19/04/2011 16:07, Mathias Burén wrote:
>>>
>>> On 19 April 2011 15:04, David Brown<david@westcontrol.com>    wrote:
>>>>
>>>> On 19/04/2011 15:25, Mathias Burén wrote:
>>>>>
>>>>> On 19 April 2011 14:21, David Brown<david@westcontrol.com>      wrote:
>>>>>>
>>>>>> I have recently got an IBM x3650 M3 server, which has a "Serveraid
>>>>>> M5014"
>>>>>> raid controller.  Booting from a Linux CD (system rescue CD) and
>>>>>> running
>>>>>> lspci identifies this raid controller as:
>>>>>>
>>>>>> LSI Logic/Symbus Logic Megaraid SAS 2108 [Liberator] (rev 03)
>>>>>>
>>>>>> The controller works fine for hardware raid - I can open its bios setup
>>>>>> utility, and set up a RAID5 (or whatever) with the disks I have.  The
>>>>>> OS
>>>>>> then just sees a single virtual disk.
>>>>>>
>>>>>> But I would like direct access to the sata drives - I want to set up
>>>>>> mdadm
>>>>>> raid, under my own control.  As far as I can see, there is no way to
>>>>>> put
>>>>>> this controller into "JBOD" or "direct access" mode of any sort.
>>>>>>
>>>>>> Does anyone here have experience with this card, or can give me any
>>>>>> hints?
>>>>>>
>>>>>> The only idea I have at the moment is to put each disk within its own
>>>>>> single-disk RAID 0 set, but then I don't get sata hot-swap
>>>>>> functionality,
>>>>>> SMART, hddtemp, etc.
>>>>>>
>>>>>> Thanks for any clues or hints,
>>>>>>
>>>>>> David
>>>>>>
>>>>>
>>>>> Regarding SMART, could you try (after loading the appropriate
>>>>> megaraid/megasas module) hdparm -a -d megaraid,$I /dev/sda , where $I
>>>>> is a number between 0 and 31 IIRC (depending on the HDD in the array).
>>>>>
>>>>
>>>> Are you sure about the syntax for that command?  Trying that with "0" for
>>>> $I
>>>> just gives me "megaraid,0: No such file or directory".  As far as I can
>>>> see,
>>>> the megaraid module is loaded (lsmod shows "megaraid_sas" in the modules
>>>> list).
>>>>
>>>> Thanks anyway,
>>>>
>>>> David
>>>>
>>>>
>>>
>>>   From the smartctl man page:
>>>
>>>           Under Linux , to look at SCSI/SAS disks behind LSI MegaRAID
>>> controllers, use syntax such as:
>>>                smartctl -a -d megaraid,2 /dev/sda
>>>                smartctl -a -d megaraid,0 /dev/sdb
>>>                where  in the argument megaraid,N, the integer N is the
>>> physical disk number within the MegaRAID controller.  This interface
>>> will also work for Dell PERC controllers.  The follow‐
>>>                ing /dev/XXX entry must exist:
>>>                For PERC2/3/4 controllers: /dev/megadev0
>>>                For PERC5/6 controllers: /dev/megaraid_sas_ioctl_node
>>>
>>> Maybe you can experiment some with that. Regards,
>>> M
>>
>> Ah, it was "smartctl" - you first wrote "hdparm".  I should have thought of
>> smartctl myself.
>>
>> Still no luck as yet - the smartctl on my test installation (Centos 5.6)
>> doesn't seem to support megaraid devices.  But maybe that's just because it
>> is an older version of smartctl - Centos 5.6 is not exactly "bleeding edge".
>>
>
> Opps, sorry! I blame the medicine. You could try compile a version of
> smartctl yourself if you have the proper packages installed.
>

The CentOs installation is only temporary.  I was doing some testing 
with IBM's software, which will only work on certain very specific Linux 
versions, such as various RHEL versions.  Since I like to use Debian on 
servers (it's what I'm used to), I didn't fancy buying RHEL just to try 
out the software - CentOS was a simple and convenient way to test the 
software.  Once I get my "real" installation in place, I can make sure I 
have up-to-date tools.

Thanks for your help and pointers,

David

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