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simopal6 02-08-2014 03:49 PM

Install Slackware 14.1 on existing RAID-0 configuration
 
Hi everyone,

I recently bought an Asus UX32VD-R4045P, which comes with two SDD drives in a BIOS RAID-0 configuration, with several partitions (EFI boot, Windows OS, Windows data -- where I meant to install Slackware --, Windows recovery, and maybe another one or two). I'm struggling to understand how to make the Slackware installer "see" its ideal installation partition.

There are a few things I don't understand, and I hope someone can give a hand :)

1) Is the installer supposed to detect the RAID-0 configuration? If so, which device files does it create? I couldn't find any /dev/md* or /dev/dm*.

2) "cgdisk /dev/sda" is able to see the logical partitions, but it warns me about several errors on the expected disk/partition sizes. I suppose this is because it does not consider the RAID-0 configuration, right? But then, how does it see the logical partitions without detecting the RAID-0?

3) Assuming I manage to actually install Slackware on the partition I mean to, am I going to be able to boot it without an out-of-RAID partition? I understood that it is the kernel which recognizes the RAID, so without loading the kernel I can't see the RAID, and without seeing the RAID I suppose I can't load the kernel, which seems quite a problem to me :)

Thanks everyone for your help!

Richard Cranium 02-08-2014 06:32 PM

BIOS RAID will not show up as /dev/md?. It will show up as a single SCSI drive (/dev/sda in your case).

The RAID controller is handling all the RAID stuff. The BIOS will simply show a unified drive to any OS that asks.


Emerson in the following post is correct; it's very unlikely that a notebook will have hardware RAID. Read his link.

Emerson 02-08-2014 08:34 PM

BIOS RAID is generally considered as fake, drives will show up as separate in Linux. Read more here.

simopal6 02-09-2014 03:43 AM

Thanks guys.

Here is what I see from the slackware installer (I'm copying by hand, so I'm trying to skip non-essential parts):


Code:

gdisk -l /dev/sda

Warning! Disk size is smaller than the main header indicates! [...]
Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: damaged

Disk /dev/sda: 119.2 GiB
[...]
Number 1    300.0 MiB    EF00    EFI System partition
Number 2    900.0 MiB    2700    Basic data partition
Number 3    128.0 MiB    0C01    Microsoft reserved partition
Number 4    92.0 GiB      0700    Basic data partition (Windows OS)
Number 5    116.7 GiB    0700    Basic data partition (where I mean to put Slackware)
Number 6    20.0 GiB      2700    Basic data partition

So, the installer recognizes how the RAID-0 setup is partitioned, but it read /dev/sda as having the size of a single physical disk (I have two disks of 128 GB each), so it thinks that the partitioning can't fit the physical space (I guess).

If I check /dev/sdb, it simply finds no partition tables, and sees the disk as having 119.2 GiB (i.e., the physical disk).

So, it seems that the kernel is able to read the RAID-0 configuration only partially: it reads the logical partitions, but still sees the physical hard drives only.

As a side note, if I go to /dev/disk/by-id, I get 4 entries (excluding the cd reader):
Code:

ata-SanDisk_SDXXX... -> /dev/sdb
ata-SanDisk_SDYYY... -> /dev/sda
wwn-0x500ZZZ... -> /dev/sdb
wwn-0x500WWW... -> /dev/sda

If I try to mount them, I get an "unknown filesystem type 'isw_raid_member'" error.

Also, I confirm that there's no /dev/md* or /dev/dm* device.

Thanks again!

simopal6 02-09-2014 04:00 AM

According to https://wiki.archlinux.org/index.php...with_Fake_RAID , it seems that the devices should appear in /dev/mapper, but I have only a "control" file there. They suggest so make sure the chipset module is loaded, so I'm going to try loading all modules I can find :)

simopal6 02-09-2014 10:20 AM

Well, I couldn't find any missing module... I'm starting to think my only way will be formatting everything and disable BIOS RAID.

Richard Cranium 02-10-2014 10:29 AM

What does "mdadm --examine /dev/sda" tell you?

It appears that mdadm might be able to support some fake raid formats. See http://www.spinics.net/lists/raid/msg44583.html

mostlyharmless 02-10-2014 12:03 PM

dmraid is usually the tool for fakeraid; once the raid0 is activated, the Windows software raid, aka Dynamic disks, can be read by mdadm if support is compiled into the kernel. (I'm not sure whether it's possible as a module). But you're probably better off starting from scratch.


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