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wildhorse
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Joined: 16 Mar 2006
Posts: 150
Location: Estados Unidos De América
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 Posted: Wed Jul 15, 2009 5:53 am Post subject: dmraid, missing partitions [solved - not really] |
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I have to deal with an nVidia MCP51 FakeRAID controller. Attached are two physical harddisks, configured as one logical mirrored disk. The devices for the individual disks (/dev/sd[ab]) exist. So do the devices for the two partitions on the disk (/dev/sd[ab][125]).
| Quote: | Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x45042d3a
Device Boot Start End Blocks Id System
/dev/sda1 * 1 4249 34130061 7 HPFS/NTFS
/dev/sda2 4250 19457 122158260 f W95 Ext'd (LBA)
/dev/sda5 4250 19457 122158228+ 7 HPFS/NTFS
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dmraid -ay found the nVidia FakeRAID system, and dmraid -s -f nvidia shows the set.
| Quote: | *** Active Set
name : nvidia_jabdcdbd
size : 312581760
stride : 128
type : mirror
status : ok
subsets: 0
devs : 2
spares : 0
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But the devices for the partitions of the RAID set are missing! 
| Quote: | # ls -la /dev/mapper/ /dev/dm*
lrwxrwxrwx 1 root root 22 Jul 14 18:43 /dev/dm-0 -> mapper/nvidia_jabdcdbd
/dev/mapper/:
total 0
drwxr-xr-x 2 root root 80 Jul 14 18:43 .
drwxr-xr-x 20 root root 4520 Jul 15 07:24 ..
lrwxrwxrwx 1 root root 16 Jul 14 18:43 control -> ../device-mapper
brw-rw---- 1 root disk 251, 0 Jul 14 18:43 nvidia_jabdcdbd
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Fdisk finds the partitions on /dev/dm-0, though. I noticed that fdisk reports 1024 bytes less for /dev/dm-0 than for /dev/sd[ab]. Not sure if that matters (guess these are the sectors used to store the RAID configuration).
| Quote: | Disk /dev/dm-0: 160.0 GB, 160041884672 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x45042d3a
Device Boot Start End Blocks Id System
/dev/dm-0p1 * 1 4249 34130061 7 HPFS/NTFS
/dev/dm-0p2 4250 19457 122158260 f W95 Ext'd (LBA)
/dev/dm-0p5 4250 19457 122158228+ 7 HPFS/NTFS
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No point in trying to mount something that is not there. Why does the kernel not discover the partitions of the RAID set?
| Quote: | | 2.6.29-gentoo-r5 x86_64 AMD Athlon(tm) 64 X2 Dual Core Processor 4800+ |
Last edited by wildhorse on Fri Jul 17, 2009 7:36 am; edited 1 time in total |
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DONAHUE
Watchman
Joined: 09 Dec 2006
Posts: 7651
Location: Goose Creek SC
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wildhorse
Apprentice
Joined: 16 Mar 2006
Posts: 150
Location: Estados Unidos De América
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| Posted: Fri Jul 17, 2009 5:56 am Post subject: |
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| My kernel is fine. And since I am not trying to boot from the RAID set and its NTFS (MS Windows) file systems, I doubt that I really need initramfs. Neither do I want genkernel. |
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wildhorse
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Joined: 16 Mar 2006
Posts: 150
Location: Estados Unidos De América
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| Posted: Fri Jul 17, 2009 7:36 am Post subject: |
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In order to check what dmraid would find, I deactivated the RAID set with dmraid -an. Then I used dmraid -ay -vvv -d and expected something that would indicate what goes wrong. However, dmraid now found the two partitions and added them to /dev/mapper/! Before, I only added an entry in /etc/dmtab for the entire RAID set (not the partitions), which I got from dmsetup table after the first dmraid -ay. The kernel and the other software remained untouched. As far as I can see from the documentation, dmraid should have found the partitions the first time and I am not sure if the entry in /etc/dmtab made a difference.
After a reboot, the partitions are still there. That is good. But somehow the whole dmraid solution does not look too trustworthy. On the long run I will try to replace this nVidia FakeRAID with a true hardware RAID solution. |
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John R. Graham
Administrator
Joined: 08 Mar 2005
Posts: 10587
Location: Somewhere over Atlanta, Georgia
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| Posted: Fri Jul 17, 2009 11:39 am Post subject: |
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Are these PATA or SATA drives?
- John
_________________
I can confirm that I have received between 0 and 499 National Security Letters. |
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wildhorse
Apprentice
Joined: 16 Mar 2006
Posts: 150
Location: Estados Unidos De América
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| Posted: Fri Jul 17, 2009 2:15 pm Post subject: |
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| john_r_graham wrote: | Are these PATA or SATA drives?
- John |
SATA |
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John R. Graham
Administrator
Joined: 08 Mar 2005
Posts: 10587
Location: Somewhere over Atlanta, Georgia
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| Posted: Fri Jul 17, 2009 2:47 pm Post subject: |
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Oh, okay. Given the size, I had guessed PATA. I was going to suggest a really nice old PATA RAID card made by Adaptec that has good Linux support (and that I have personal experience with). I am a strong believer in using generation-before-last server technology to produce high-performance, highly reliable home servers and desktops. 
- John
_________________
I can confirm that I have received between 0 and 499 National Security Letters. |
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wildhorse
Apprentice
Joined: 16 Mar 2006
Posts: 150
Location: Estados Unidos De América
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| Posted: Sat Jul 18, 2009 2:46 pm Post subject: |
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| Sure, there are plenty of good alternatives to those damn nVidia FakeRAID interfaces, even for PATA. But in this particular case I cannot change the configuration. |
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cengique
n00b
Joined: 17 Mar 2012
Posts: 13
Location: United States
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| Posted: Sat Mar 17, 2012 8:10 pm Post subject: solved by using 'dmraid -ay -f nvidia' |
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I had a similar problem with 'dmraid -ay' not finding the partitions although it finds the nvidia swraid properly.
It turns out, it was also trying to get the Intel swraid after that and was choking on that probably because it was already handled by mdadm.
So, when I pushed dmraid only to process the nvidia swraid with:
| Code: | | dmraid -ay -f nvidia |
And, it worked! |
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