Howto: implement AMD SB9xx RAID5 support in dmraid

Fri Apr 13 07:41:21 UTC 2012

Hi All,

Just checked the other device-mapper modules used by dmraid, and 
by changing _dm_path_offset I broke the support for the other raid 
devices. So, I need to  make a separate function for raid4/5/6.

I will also put back the rebuild and region_size information. 
The region_size information is simple only the rebuild parameter
does not except -1, so there will be some conditionals added to the code.

Are there any devs who are willing to help get dmraid to support all 
the device-mapper modules in the present kernel?

Greetings,

Mark-Willem
Date: Fri, 13 Apr 2012 11:00:10 +0400
From: astarta at rat.ru
To: markwillem at hotmail.com
CC: ataraid-list at redhat.com
Subject: Re: Howto: implement AMD SB9xx RAID5 support in dmraid

    Hello Mark-Willem,

    Good research! Thank you for sharing.

    --

    Mary

    On 04/13/2012 03:23 AM, Mark-Willem Jansen wrote:

      Hi,

        Been playing with the patches you gave me. And I finally got the
        raid up and running, using the shipped dm-raid.ko module in the
        3.2 kernel.

        Lets go through the steps.

        I have applied the dmraid_pdc_raid5.patch, this caused dmraid to
        produce a new error related to the missing dm-raid45 module.
        Before activating a new raid set  dmraid checks if a dm-target
        has been registered with device-mapper. This can be changed
        through a struct in metadata.c. Doing this accordingly only left
        me with the error of raid array not activated. Going through the
        dmesg I found that dmraid was giving a wrong raid type to the
        dm-raid module. Digging deeper I wound that the arguments given
        to dm-raid45 and dm-raid have a different structure. So I have
        changed the arguments structure send to the module accordingly.

        $ dmraid -ay -t

        pdc_ciihdaafgf: 0 1953124864 raid raid5_la 2 128 nosync 3 -
        /dev/sdb - /dev/sdc - /dev/sdd

        this used to be something like (I forgot some numbers)

        $ dmraid -ay -t

        pdc_ciihdaafgf: 0 1953124864 raid core 2 132016 nosync raid5_la
        1 128 3 -1 /dev/sdb 0 /dev/sdc 0 /dev/sdd 0

        The patch has been attached. (see that I have made some typo's
        in naming the patch.)

        Now I can activate the raid and by using kpartx I can also mount
        the partitions on the raid. Whoot.

        Unfortunately the fix was a bit dirty, could be that I have
        broken dmraid for the other raid types. Also I am not sure if
        you need to send the region_size to the dm-raid module.

        Regards,

        Mark-Willem

          Date: Tue, 3 Apr 2012 11:13:20 +0400

          From: astarta at rat.ru

          To: markwillem at hotmail.com

          CC: ataraid-list at redhat.com

          Subject: Re: Howto: implement AMD SB9xx RAID5 support in
          dmraid

          Hello,

          I do have dm-raid45 patch for 3.2. 

          I do not remember where it was taken from, but it compiles
          with 3.2 :-)

          On 04/03/2012 11:13 AM, Mark-Willem Jansen wrote:

             Hello,

              Later this day I will apply the patch. But patching the
              kernel will be more cumbersome. The 

              present kernel running om my system is 3.2.0 and the
              patches found on the web are for 

              older kernels. But maybe the module dm-raid.ko included in
              the kernel can be helpful.

              Regards,

              Mark-Willem

              > Date: Mon, 2 Apr 2012 17:42:12 +0400

                > From: astarta at rat.ru

                > To: markwillem at hotmail.com

                > CC: psusi at ubuntu.com

                > Subject: Re: Howto: implement AMD SB9xx RAID5
                support in dmraid

                > 

                > hello,

                > 

                > You may try the attached patch to support RAID5 in
                pdc dmraid format. It 

                > works OK for me.

                > Be sure to patch the kernel itself to support
                dm-raid45 target.

                > 

                > 

                > On 04/02/2012 02:59 AM, Phillip Susi wrote:

                > > -----BEGIN PGP SIGNED MESSAGE-----

                > > Hash: SHA1

                > >

                > > On 04/01/2012 04:21 PM, Mark-Willem Jansen
                wrote:

                > >> ERROR: pdc: zero sectors on /dev/sdd

                > >> ERROR: pdc: setting up RAID device
                /dev/sdd

                > > It looks like sectors() in pdc.c is missing
                the case for computing the size of a RAID5. For that
                matter, there appears to be no #define for PDC_T_RAID5,
                so you will need to add one and add it to the mapping
                table in type() and fix sectors() to handle it and
                probably a few other things.

                > >

                > >

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                > 

                > -- 

                > С уважением,

                > Astarta

                > Администратор Форума "Крысиный Бум"

                > http://rat.ru/forum/index.php

                > 

                > “The Linux philosophy is 'Laugh in the face of
                danger'.

                > Oops. Wrong One. 'Do it yourself'. Yes, that's it.”

                > (c) Linus Torvalds.

                > 

          -- 
С уважением,
Astarta
Администратор Форума "Крысиный Бум"
http://rat.ru/forum/index.php

“The Linux philosophy is 'Laugh in the face of danger'.
Oops. Wrong One. 'Do it yourself'. Yes, that's it.”
(c) Linus Torvalds. 

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