grub RAID heuristics (how can we avoid "superfluous RAID member (2 found)")

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* grub RAID heuristics (how can we avoid "superfluous RAID member (2 found)")
@ 2012-02-02  0:55 Daniel Kahn Gillmor
  2012-02-23  5:43 ` Vladimir 'φ-coder/phcoder' Serbinenko
  0 siblings, 1 reply; 5+ messages in thread
From: Daniel Kahn Gillmor @ 2012-02-02  0:55 UTC (permalink / raw)
  To: grub-devel

hi folks--

i was speaking with phcoder today on #grub, about getting messages like
this from grub when a partition that is part of a Linux SW RAID set
(with metadata 0.9x) is close to the end of its containing block device:

  superfluous RAID member (2 found)

Here's phcoder's explanation of the problem:

> 16:08 < phcoder> if you have < 64KiB between end of disk and end of partition 
>                  the metadata is exactly in the same place for either if the 
>                  whole disks are raided or only partitions. And no field which 
>                  allows to distinguish those
 [...]
> 16:09 < phcoder> thing is that mdraid format rounds it down to a 64K aligned 
>                  boundary
> 16:10 < dkg0> 64KiB aligned to the parent disk, or to the partition itself?
> 16:10 < phcoder> to whatever the host of the raid is. For your error to occur 
>                  it has to be both
> 16:10 < dkg0> hm, i suppose if the partition itself starts evenly aligned with 
>               a 64KiB boundary, it'd be the same thing.

It sounds like there might be some circumstances (e.g. a RAID0 set of
sda and sdb, creating md0, and a partition table on top of md0) where it
is legitimately difficult to decide the correct interpretation.

However, i think there might be a reasonable heuristic that can be used
in the case of RAID1 sets that would avoid the ambiguity (and the scary
messages/warnings to the user:

Select the smallest known block device that can completely enclose the
RAID member.  The larger block device(s) should not be considered to be
exporting that RAID.

these heuristics would mean that RAID1 sets with 0.9x metadata on any
sort of disklabel would only have their member components show up once
during a scan, rather than treating them as a duplicate.

phcoder mentioned that the RAID code was undergoing something of an
overhaul.  perhaps these heuristics could play into that update?

I'm not sure how to address it with RAID0 or RAID10, but if we could fix
the RAID1 case, that would be a big win for a lot of users.

Regards,

	--dkg

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: grub RAID heuristics (how can we avoid "superfluous RAID member (2 found)")
  2012-02-02  0:55 grub RAID heuristics (how can we avoid "superfluous RAID member (2 found)") Daniel Kahn Gillmor
@ 2012-02-23  5:43 ` Vladimir 'φ-coder/phcoder' Serbinenko
  2012-02-24  5:41   ` Daniel Kahn Gillmor
  2012-02-25 21:49   ` Daniel Kahn Gillmor
  0 siblings, 2 replies; 5+ messages in thread
From: Vladimir 'φ-coder/phcoder' Serbinenko @ 2012-02-23  5:43 UTC (permalink / raw)
  To: grub-devel

[-- Attachment #1: Type: text/plain, Size: 2436 bytes --]

On 02.02.2012 01:55, Daniel Kahn Gillmor wrote:
> hi folks--
>
> i was speaking with phcoder today on #grub, about getting messages like
> this from grub when a partition that is part of a Linux SW RAID set
> (with metadata 0.9x) is close to the end of its containing block device:
>
>    superfluous RAID member (2 found)
Try attached patch
> Here's phcoder's explanation of the problem:
>
>> 16:08<  phcoder>  if you have<  64KiB between end of disk and end of partition
>>                   the metadata is exactly in the same place for either if the
>>                   whole disks are raided or only partitions. And no field which
>>                   allows to distinguish those
>   [...]
>> 16:09<  phcoder>  thing is that mdraid format rounds it down to a 64K aligned
>>                   boundary
>> 16:10<  dkg0>  64KiB aligned to the parent disk, or to the partition itself?
>> 16:10<  phcoder>  to whatever the host of the raid is. For your error to occur
>>                   it has to be both
>> 16:10<  dkg0>  hm, i suppose if the partition itself starts evenly aligned with
>>                a 64KiB boundary, it'd be the same thing.
>
> It sounds like there might be some circumstances (e.g. a RAID0 set of
> sda and sdb, creating md0, and a partition table on top of md0) where it
> is legitimately difficult to decide the correct interpretation.
>
> However, i think there might be a reasonable heuristic that can be used
> in the case of RAID1 sets that would avoid the ambiguity (and the scary
> messages/warnings to the user:
>
> Select the smallest known block device that can completely enclose the
> RAID member.  The larger block device(s) should not be considered to be
> exporting that RAID.
>
> these heuristics would mean that RAID1 sets with 0.9x metadata on any
> sort of disklabel would only have their member components show up once
> during a scan, rather than treating them as a duplicate.
>
> phcoder mentioned that the RAID code was undergoing something of an
> overhaul.  perhaps these heuristics could play into that update?
>
> I'm not sure how to address it with RAID0 or RAID10, but if we could fix
> the RAID1 case, that would be a big win for a lot of users.
>
> Regards,
>
> 	--dkg
>
> _______________________________________________
> Grub-devel mailing list
> Grub-devel@gnu.org
> https://lists.gnu.org/mailman/listinfo/grub-devel
>


-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko


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=== modified file 'grub-core/disk/diskfilter.c'
--- grub-core/disk/diskfilter.c	2012-02-12 14:25:25 +0000
+++ grub-core/disk/diskfilter.c	2012-02-23 05:42:14 +0000
@@ -972,35 +972,40 @@
 	: (pv->id.id == id->id))
       {
 	struct grub_diskfilter_lv *lv;
+	grub_disk_t disk;
 	/* FIXME: Check whether the update time of the superblocks are
 	   the same.  */
+	disk = grub_disk_open (disk->name);
+	if (!disk)
+	  return grub_errno;
+	if (disk && pv->disk && grub_disk_get_size (disk) >= pv->part_size)
+	  {
+	    grub_disk_close (disk);
+	    return GRUB_ERR_NONE;
+	  }
+	pv->disk = disk;
 	/* This could happen to LVM on RAID, pv->disk points to the
 	   raid device, we shouldn't change it.  */
-	if (! pv->disk)
-	  {
-	    pv->disk = grub_disk_open (disk->name);
-	    if (! pv->disk)
-	      return grub_errno;
-	    pv->part_start = grub_partition_get_start (disk->partition);
-	    pv->part_size = grub_disk_get_size (disk);
+	pv->start_sector -= pv->part_start;
+	pv->part_start = grub_partition_get_start (disk->partition);
+	pv->part_size = grub_disk_get_size (disk);
 
 #ifdef GRUB_UTIL
-	    {
-	      grub_size_t s = 1;
-	      grub_partition_t p;
-	      for (p = disk->partition; p; p = p->parent)
-		s++;
-	      pv->partmaps = xmalloc (s * sizeof (pv->partmaps[0]));
-	      s = 0;
-	      for (p = disk->partition; p; p = p->parent)
-		pv->partmaps[s++] = xstrdup (p->partmap->name);
-	      pv->partmaps[s++] = 0;
-	    }
+	{
+	  grub_size_t s = 1;
+	  grub_partition_t p;
+	  for (p = disk->partition; p; p = p->parent)
+	    s++;
+	  pv->partmaps = xmalloc (s * sizeof (pv->partmaps[0]));
+	  s = 0;
+	  for (p = disk->partition; p; p = p->parent)
+	    pv->partmaps[s++] = xstrdup (p->partmap->name);
+	  pv->partmaps[s++] = 0;
+	}
 #endif
-	    if (start_sector != (grub_uint64_t)-1)
-	      pv->start_sector = start_sector;
-	    pv->start_sector += pv->part_start;
-	  }
+	if (start_sector != (grub_uint64_t)-1)
+	  pv->start_sector = start_sector;
+	pv->start_sector += pv->part_start;
 	/* Add the device to the array. */
 	for (lv = array->lvs; lv; lv = lv->next)
 	  if (!lv->became_readable_at && lv->fullname && is_lv_readable (lv))


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: grub RAID heuristics (how can we avoid "superfluous RAID member (2 found)")
  2012-02-23  5:43 ` Vladimir 'φ-coder/phcoder' Serbinenko
@ 2012-02-24  5:41   ` Daniel Kahn Gillmor
  2012-02-25 21:49   ` Daniel Kahn Gillmor
  1 sibling, 0 replies; 5+ messages in thread
From: Daniel Kahn Gillmor @ 2012-02-24  5:41 UTC (permalink / raw)
  To: Vladimir 'φ-coder/phcoder' Serbinenko, grub-devel

[-- Attachment #1: Type: text/plain, Size: 7491 bytes --]

On Thu, 23 Feb 2012 06:43:23 +0100, Vladimir 'φ-coder/phcoder' Serbinenko <phcoder@gmail.com> wrote:
> Try attached patch

hrm, i get a segmentation fault from "grub-probe /" even without this
patch when building from bzr trunk (r3964, i think).

The test machine i've set up looks like this uses a common layering
scheme:
 disk → partition → mdadm (0.90 superblock) → lvm → filesystem

Here are the details and a backtrace of me trying:

0 root@trash:~# parted /dev/sda unit s print
Model: ATA WDC WD200BB-75DE (scsi)
Disk /dev/sda: 39062500s
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start      End        Size       Type     File system  Flags
 1      8192s      12542018s  12533827s  primary
 2      12550144s  39062499s  26512356s  primary

0 root@trash:~# parted /dev/sdb unit s print
Model: ATA QUANTUM FIREBALL (scsi)
Disk /dev/sdb: 26520480s
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start  End        Size       Type     File system  Flags
 1      4096s  26520479s  26516384s  primary

0 root@trash:~# cat /proc/mdstat 
Personalities : [raid1] 
md0 : active raid1 sdb1[0] sda2[1]
      13256064 blocks [2/2] [UU]

unused devices: <none>
0 root@trash:~# pvs
  PV         VG        Fmt  Attr PSize  PFree
  /dev/md0   vg_trash0 lvm2 a--  12.64g 9.64g
0 root@trash:~# vgs
  VG        #PV #LV #SN Attr   VSize  VFree
  vg_trash0   1   1   0 wz--n- 12.64g 9.64g
0 root@trash:~# lvs
  LV   VG        Attr   LSize Origin Snap%  Move Log Copy%  Convert
  root vg_trash0 -wi-ao 3.00g                                      
0 root@trash:~# grep ' / ' /proc/mounts 
rootfs / rootfs rw 0 0
/dev/mapper/vg_trash0-root / ext3 rw,relatime,errors=remount-ro,user_xattr,acl,barrier=1,data=ordered 0 0
0 root@trash:~# cd - 
/home/dkg/src/grub/grub
0 root@trash:/home/dkg/src/grub/grub# gdb ./grub-probe
GNU gdb (GDB) 7.4-debian
Copyright (C) 2012 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "i486-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /home/dkg/src/grub/grub/grub-probe...(no debugging symbols found)...done.
(gdb) run -v /
Starting program: /home/dkg/src/grub/grub/grub-probe -v /
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/i386-linux-gnu/libthread_db.so.1".
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to /dev/mapper.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to /dev.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to md.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to dri.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to snd.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to by-path.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to cpu.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to vg_trash0.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to /dev.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to md.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to dri.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to snd.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to by-path.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to cpu.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to vg_trash0.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to disk.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to by-uuid.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to by-path.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to by-id.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to block.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to /dev.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to md.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to dri.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to snd.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to by-path.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to cpu.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to vg_trash0.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to disk.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to by-uuid.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to by-path.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to by-id.
/home/dkg/src/grub/grub/grub-probe: info: changing current directory to block.
/home/dkg/src/grub/grub/grub-probe: info: Looking for /dev/sdb1.
/home/dkg/src/grub/grub/grub-probe: info: /dev/sdb1 starts from 4096.
/home/dkg/src/grub/grub/grub-probe: info: opening the device hd1.
/home/dkg/src/grub/grub/grub-probe: info: the size of hd1 is 26520480.
/home/dkg/src/grub/grub/grub-probe: info: the size of hd1 is 26520480.
/home/dkg/src/grub/grub/grub-probe: info: Scanning for DISKFILTER devices on disk hd1.
/home/dkg/src/grub/grub/grub-probe: info: no LVM signature found.
/home/dkg/src/grub/grub/grub-probe: info: Found array md/md0.
/home/dkg/src/grub/grub/grub-probe: info: Inserting hd1 into md/md0 (mdraid09)
.
/home/dkg/src/grub/grub/grub-probe: info: the size of hd1 is 26520480.
/home/dkg/src/grub/grub/grub-probe: info: Scanning for DISKFILTER devices on disk md/md0.
/home/dkg/src/grub/grub/grub-probe: info: no LVM signature found.
/home/dkg/src/grub/grub/grub-probe: info: scanning md/md0 for LDM.
/home/dkg/src/grub/grub/grub-probe: info: no LDM signature found.
/home/dkg/src/grub/grub/grub-probe: info: Scanning for DISKFILTER devices on disk md/md0.
/home/dkg/src/grub/grub/grub-probe: info: Found array vg_trash0.
/home/dkg/src/grub/grub/grub-probe: info: Inserting md/md0 into vg_trash0 (lvm)
.
/home/dkg/src/grub/grub/grub-probe: info: Scanning for DISKFILTER devices on disk lvm/vg_trash0-root.
/home/dkg/src/grub/grub/grub-probe: info: no LVM signature found.
/home/dkg/src/grub/grub/grub-probe: info: scanning lvm/vg_trash0-root for LDM.
/home/dkg/src/grub/grub/grub-probe: info: no LDM signature found.
/home/dkg/src/grub/grub/grub-probe: info: Scanning for DISKFILTER devices on disk hd1.
/home/dkg/src/grub/grub/grub-probe: info: Inserting hd1 into vg_trash0 (lvm)
.

Program received signal SIGSEGV, Segmentation fault.
0x080e7850 in grub_util_get_ldm ()
(gdb) bt
#0  0x080e7850 in grub_util_get_ldm ()
#1  0x080d834e in grub_util_biosdisk_get_grub_dev ()
#2  0x080d7195 in grub_util_pull_device ()
#3  0x080d716a in grub_util_pull_device ()
#4  0x080d7081 in grub_util_pull_device ()
#5  0x0804ab2c in probe ()
#6  0x0804bcdc in main ()
(gdb) 

Applying the patch doesn't help me avoid the segfault.

So i haven't really tested the patch.

   --dkg

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^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: grub RAID heuristics (how can we avoid "superfluous RAID member (2 found)")
  2012-02-23  5:43 ` Vladimir 'φ-coder/phcoder' Serbinenko
  2012-02-24  5:41   ` Daniel Kahn Gillmor
@ 2012-02-25 21:49   ` Daniel Kahn Gillmor
  2012-02-27  3:29     ` Daniel Kahn Gillmor
  1 sibling, 1 reply; 5+ messages in thread
From: Daniel Kahn Gillmor @ 2012-02-25 21:49 UTC (permalink / raw)
  To: Vladimir 'φ-coder/phcoder' Serbinenko, grub-devel


[-- Attachment #1.1: Type: text/plain, Size: 985 bytes --]

On Thu, 23 Feb 2012 06:43:23 +0100, Vladimir 'φ-coder/phcoder' Serbinenko <phcoder@gmail.com> wrote:
> [dkg wrote:]
> > Select the smallest known block device that can completely enclose the
> > RAID member.  The larger block device(s) should not be considered to be
> > exporting that RAID.

phcoder pointed me to the attached patch for improved heuristics for
this case, which applies cleanly to the current head of bzr.  Applied,
it removes the spurious error messages from grub-probe, as seen here
compared against debian's grub-probe 1.99-14:

0 root@trash:/home/dkg/src/grub/grub# grub-probe --target=device /
error: found two disks with the index 1 for RAID md0.
error: superfluous RAID member (2 found).
/dev/mapper/vg_trash0-root
0 root@trash:/home/dkg/src/grub/grub# ./grub-probe --target=device /
/dev/mapper/vg_trash0-root
0 root@trash:/home/dkg/src/grub/grub# 

I think it's worth applying.

Thanks for your work on this, phcoder!

       --dkg


[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1.2: grub-raid-heuristics.patch --]
[-- Type: text/x-diff, Size: 3067 bytes --]

=== modified file 'grub-core/disk/diskfilter.c'
--- grub-core/disk/diskfilter.c	2012-02-12 14:25:25 +0000
+++ grub-core/disk/diskfilter.c	2012-02-24 21:06:10 +0000
@@ -974,33 +974,33 @@
 	struct grub_diskfilter_lv *lv;
 	/* FIXME: Check whether the update time of the superblocks are
 	   the same.  */
+	if (pv->disk && grub_disk_get_size (disk) >= pv->part_size)
+	  return GRUB_ERR_NONE;
+	pv->disk = grub_disk_open (disk->name);
+	if (!pv->disk)
+	  return grub_errno;
 	/* This could happen to LVM on RAID, pv->disk points to the
 	   raid device, we shouldn't change it.  */
-	if (! pv->disk)
-	  {
-	    pv->disk = grub_disk_open (disk->name);
-	    if (! pv->disk)
-	      return grub_errno;
-	    pv->part_start = grub_partition_get_start (disk->partition);
-	    pv->part_size = grub_disk_get_size (disk);
+	pv->start_sector -= pv->part_start;
+	pv->part_start = grub_partition_get_start (disk->partition);
+	pv->part_size = grub_disk_get_size (disk);
 
 #ifdef GRUB_UTIL
-	    {
-	      grub_size_t s = 1;
-	      grub_partition_t p;
-	      for (p = disk->partition; p; p = p->parent)
-		s++;
-	      pv->partmaps = xmalloc (s * sizeof (pv->partmaps[0]));
-	      s = 0;
-	      for (p = disk->partition; p; p = p->parent)
-		pv->partmaps[s++] = xstrdup (p->partmap->name);
-	      pv->partmaps[s++] = 0;
-	    }
+	{
+	  grub_size_t s = 1;
+	  grub_partition_t p;
+	  for (p = disk->partition; p; p = p->parent)
+	    s++;
+	  pv->partmaps = xmalloc (s * sizeof (pv->partmaps[0]));
+	  s = 0;
+	  for (p = disk->partition; p; p = p->parent)
+	    pv->partmaps[s++] = xstrdup (p->partmap->name);
+	  pv->partmaps[s++] = 0;
+	}
 #endif
-	    if (start_sector != (grub_uint64_t)-1)
-	      pv->start_sector = start_sector;
-	    pv->start_sector += pv->part_start;
-	  }
+	if (start_sector != (grub_uint64_t)-1)
+	  pv->start_sector = start_sector;
+	pv->start_sector += pv->part_start;
 	/* Add the device to the array. */
 	for (lv = array->lvs; lv; lv = lv->next)
 	  if (!lv->became_readable_at && lv->fullname && is_lv_readable (lv))

=== modified file 'grub-core/disk/mdraid_linux.c'
--- grub-core/disk/mdraid_linux.c	2012-01-29 13:28:01 +0000
+++ grub-core/disk/mdraid_linux.c	2012-02-24 21:11:29 +0000
@@ -201,6 +201,11 @@
       return NULL;
     }
 
+  /* No need for explicit check that sb.size is 0 (unspecified) since
+     0 >= non-0 is false.  */
+  if (((grub_disk_addr_t) grub_le_to_cpu32 (sb.size)) * 2 >= size)
+    return NULL;
+
   /* FIXME: Check the checksum.  */
 
   level = grub_le_to_cpu32 (sb.level);
@@ -241,7 +246,8 @@
   grub_snprintf (buf, sizeof (buf), "md%d", grub_le_to_cpu32 (sb.md_minor));
   return grub_diskfilter_make_raid (16, (char *) uuid,
 				    grub_le_to_cpu32 (sb.raid_disks), buf,
-				    (sb.size) ? grub_le_to_cpu32 (sb.size) * 2 
+				    (sb.size) ? ((grub_disk_addr_t)
+						 grub_le_to_cpu32 (sb.size)) * 2
 				    : sector,
 				    grub_le_to_cpu32 (sb.chunk_size) >> 9,
 				    grub_le_to_cpu32 (sb.layout),


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^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: grub RAID heuristics (how can we avoid "superfluous RAID member (2 found)")
  2012-02-25 21:49   ` Daniel Kahn Gillmor
@ 2012-02-27  3:29     ` Daniel Kahn Gillmor
  0 siblings, 0 replies; 5+ messages in thread
From: Daniel Kahn Gillmor @ 2012-02-27  3:29 UTC (permalink / raw)
  To: Vladimir 'φ-coder/phcoder' Serbinenko, grub-devel

[-- Attachment #1: Type: text/plain, Size: 2221 bytes --]

On Sat, 25 Feb 2012 16:49:00 -0500, Daniel Kahn Gillmor <dkg@fifthhorseman.net> wrote:
> On Thu, 23 Feb 2012 06:43:23 +0100, Vladimir 'φ-coder/phcoder' Serbinenko <phcoder@gmail.com> wrote:
> > [dkg wrote:]
> > > Select the smallest known block device that can completely enclose the
> > > RAID member.  The larger block device(s) should not be considered to be
> > > exporting that RAID.

I just built the latest (r4008) bzr head, which i believe includes the
proposed changes, and installed it on a machine with two disks in RAID1:

0 root@trash:/home/dkg/src/grub/grub# cat /proc/partitions 
major minor  #blocks  name

   8        0   19531250 sda
   8        1    6266913 sda1
   8        2   13256178 sda2
   8       16   13260240 sdb
   8       17   13258192 sdb1
   9        0   13256064 md0
 253        0    3145728 dm-0
0 root@trash:/home/dkg/src/grub/grub# cat /proc/mdstat 
Personalities : [raid1] 
md0 : active raid1 sdb1[0] sda2[1]
      13256064 blocks [2/2] [UU]
      
unused devices: <none>
0 root@trash:/home/dkg/src/grub/grub# pvs
  PV         VG        Fmt  Attr PSize  PFree
  /dev/md0   vg_trash0 lvm2 a--  12.64g 9.64g
0 root@trash:/home/dkg/src/grub/grub# vgs
  VG        #PV #LV #SN Attr   VSize  VFree
  vg_trash0   1   1   0 wz--n- 12.64g 9.64g
0 root@trash:/home/dkg/src/grub/grub# lvs
  LV   VG        Attr   LSize Origin Snap%  Move Log Copy%  Convert
  root vg_trash0 -wi-ao 3.00g                                      
0 root@trash:/home/dkg/src/grub/grub# 


it boots correctly on this setup, yay!

booting to the grub command line, however, i do see some weirdness:

grub> ls
(lvm/vg_trash0-root) (hd0) (hd0,msdos2) (hd0,msdos1) (hd1) (hd1,msdos1)
(fd0) (lvm/vg_trash0-root)

grub> insmod mdraid09
grub> ls
(lvm/vg_trash0-root) (hd0) (hd0,msdos2) (hd0,msdos1) (hd1) (hd1,msdos1)
(fd0) (md/md0) (md/md0,msdos2) (md/md0,msdos1) (lvm/vg_trash0-root)

grub> rmmod mdraid09
grub> ls
(md/md0) (lvm/vg_trash0-root) (hd0) (hd0,msdos2) (hd0,msdos1) (hd1)
(hd1,msdos1) (fd0) (md/md0)

grub> insmod mdraid09
grub> ls
(md/md0) (lvm/vg_trash0-root) (hd0) (hd0,msdos2) (hd0,msdos1) (hd1)
(hd1,msdos1) (fd0) (md/md0)


             --dkg

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^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2012-02-27  3:28 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2012-02-02  0:55 grub RAID heuristics (how can we avoid "superfluous RAID member (2 found)") Daniel Kahn Gillmor
2012-02-23  5:43 ` Vladimir 'φ-coder/phcoder' Serbinenko
2012-02-24  5:41   ` Daniel Kahn Gillmor
2012-02-25 21:49   ` Daniel Kahn Gillmor
2012-02-27  3:29     ` Daniel Kahn Gillmor

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