Re: Kernel 2.6.17 and RAID5 Grow Problem (critical section backup)

From: Justin Piszcz
Date: Fri Jul 07 2006 - 15:02:58 EST



On Fri, 7 Jul 2006, Justin Piszcz wrote:



On Fri, 7 Jul 2006, Justin Piszcz wrote:

On Fri, 7 Jul 2006, Justin Piszcz wrote:

On Fri, 7 Jul 2006, Justin Piszcz wrote:

p34:~# mdadm /dev/md3 -a /dev/hde1
mdadm: added /dev/hde1

p34:~# mdadm -D /dev/md3
/dev/md3:
Version : 00.90.03
Creation Time : Fri Jun 30 09:17:12 2006
Raid Level : raid5
Array Size : 1953543680 (1863.04 GiB 2000.43 GB)
Device Size : 390708736 (372.61 GiB 400.09 GB)
Raid Devices : 6
Total Devices : 7
Preferred Minor : 3
Persistence : Superblock is persistent

Update Time : Fri Jul 7 08:25:44 2006
State : clean
Active Devices : 6
Working Devices : 7
Failed Devices : 0
Spare Devices : 1

Layout : left-symmetric
Chunk Size : 512K

UUID : e76e403c:7811eb65:73be2f3b:0c2fc2ce
Events : 0.232940

Number Major Minor RaidDevice State
0 22 1 0 active sync /dev/hdc1
1 56 1 1 active sync /dev/hdi1
2 3 1 2 active sync /dev/hda1
3 8 49 3 active sync /dev/sdd1
4 88 1 4 active sync /dev/hdm1
5 8 33 5 active sync /dev/sdc1

6 33 1 - spare /dev/hde1
p34:~# mdadm --grow /dev/md3 --raid-disks=7
mdadm: Need to backup 15360K of critical section..
mdadm: Cannot set device size/shape for /dev/md3: No space left on device
p34:~# mdadm --grow /dev/md3 --bitmap=internal --raid-disks=7
mdadm: can change at most one of size, raiddisks, bitmap, and layout
p34:~# umount /dev/md3
p34:~# mdadm --grow /dev/md3 --raid-disks=7
mdadm: Need to backup 15360K of critical section..
mdadm: Cannot set device size/shape for /dev/md3: No space left on device
p34:~#

The disk only has about 350GB of 1.8TB used, any idea why I get this error?

I searched google but could not find anything on this issue when trying to grow the array?


-
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html


Is it because I use a 512kb chunksize?

Jul 7 08:44:59 p34 kernel: [4295845.933000] raid5: reshape: not enough stripes. Needed 512
Jul 7 08:44:59 p34 kernel: [4295845.962000] md: couldn't update array info. -28

So the RAID5 reshape only works if you use a 128kb or smaller chunk size?

Justin.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/


From the source:

/* Can only proceed if there are plenty of stripe_heads.
@@ -2599,30 +2593,48 @@ static int raid5_reshape(mddev_t *mddev,
* If the chunk size is greater, user-space should request more
* stripe_heads first.
*/
- if ((mddev->chunk_size / STRIPE_SIZE) * 4 > conf->max_nr_stripes) {
+ if ((mddev->chunk_size / STRIPE_SIZE) * 4 > conf->max_nr_stripes ||
+ (mddev->new_chunk / STRIPE_SIZE) * 4 > conf->max_nr_stripes) {
printk(KERN_WARNING "raid5: reshape: not enough stripes. Needed %lu\n",
(mddev->chunk_size / STRIPE_SIZE)*4);
return -ENOSPC;
}

I don't see anything that mentions one needs to use a certain chunk size?

Any idea what the problem is here?

Justin.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/


Neil,

Any comments?

Justin.


The --grow option worked, sort of.

p34:~# mdadm /dev/md3 --grow --size=max
p34:~# umount /dev/md3
p34:~# mdadm -S /dev/md3
p34:~# mount /dev/md3
Segmentation fault
p34:~#

[4313355.425000] BUG: unable to handle kernel NULL pointer dereference at virtual address 000000d4
[4313355.425000] printing eip:
[4313355.425000] c03c377b
[4313355.425000] *pde = 00000000
[4313355.425000] Oops: 0002 [#1]
[4313355.425000] PREEMPT SMP
[4313355.425000] CPU: 0
[4313355.425000] EIP: 0060:[<c03c377b>] Not tainted VLI
[4313355.425000] EFLAGS: 00010046 (2.6.17.3 #4)
[4313355.425000] EIP is at _spin_lock_irqsave+0x14/0x61
[4313355.425000] eax: 00000000 ebx: f7e6c000 ecx: c0333d12 edx: 00000202
[4313355.425000] esi: 000000d4 edi: f7fb9600 ebp: 000000d4 esp: f7e6dc94
[4313355.425000] ds: 007b es: 007b ss: 0068
[4313355.425000] Process mount (pid: 22892, threadinfo=f7e6c000 task=c1a90580)
[4313355.425000] Stack: c19947e4 00000000 c0333d32 00000002 c012aaa2 f7e6dccc f7e6dc9c f7e6dc9c
[4313355.425000] f7e6dccc c0266b8d c19947e4 00000000 00000000 e11a61f8 f7e6dccc f7e6dccc
[4313355.425000] 00000005 f7fda014 f7fda000 f7fe8c00 c0259a79 e11a61c0 00000001 0000001f
[4313355.425000] Call Trace:
[4313355.425000] <c0333d32> raid5_unplug_device+0x20/0x65 <c012aaa2> flush_workqueue+0x67/0x87
[4313355.425000] <c0266b8d> xfs_flush_buftarg+0x1ab/0x1c1 <c0259a79> xfs_mount+0x322/0xbb5
[4313355.425000] <c013e3f2> truncate_inode_pages+0x2f/0x33 <c015c3e5> set_blocksize+0x83/0x91
[4313355.425000] <c026d804> xfs_fs_fill_super+0x94/0x232 <c02825b3> snprintf+0x2b/0x2f
[4313355.425000] <c0189c8e> disk_name+0xa9/0xb3 <c015c412> sb_set_blocksize+0x1f/0x46
[4313355.425000] <c015b5ff> get_sb_bdev+0x100/0x13f <c016f104> alloc_vfsmnt+0xab/0xd4
[4313355.425000] <c026ce9e> xfs_fs_get_sb+0x2f/0x33 <c026d770> xfs_fs_fill_super+0x0/0x232
[4313355.425000] <c015abc4> do_kern_mount+0x49/0xc0 <c016ffc5> do_mount+0x2c7/0x6e6
[4313355.425000] <c014372e> __handle_mm_fault+0x1fb/0x8a2 <c01439c2> __handle_mm_fault+0x48f/0x8a2
[4313355.425000] <c013b6f5> __alloc_pages+0x53/0x2f1 <c013bbd2> __get_free_pages+0x2d/0x4b
[4313355.425000] <c016ede0> copy_mount_options+0x2c/0x12e <c0170481> sys_mount+0x9d/0xde
[4313355.425000] <c0102df3> syscall_call+0x7/0xb
[4313355.425000] Code: 85 c0 74 c3 f3 90 0f b6 06 84 c0 7e f0 eb b8 90 e8 60 f2 ff ff eb d1 56 53 89 c6 bb 00 e0 ff ff 21 e3 83 43 14 01 9c 5a fa 31 c0 <86> 06 84 c0 7e 0c c7 46 04 00 00 00 00 89 d0 5b 5e c3 52 9d 83
[4313355.425000] EIP: [<c03c377b>] _spin_lock_irqsave+0x14/0x61 SS:ESP 0068:f7e6dc94
[4313355.425000] <6>note: mount[22892] exited with preempt_count 1


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/