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Trouble building a RAID 4 array with mdadm

Kevin O'Gorman
I'm on Xubuntu 16.04.2 LTS, using mdadm.  I've already built a RAID-1 array and had some success with it.  I'm trying to build a RAID 5 array, and having troubles.

I'm using the instructions I found on DigitalOcean (http://goo.gl/ZzwyxQ)

I did the mdadm --create, thus:
mdadm --create --verbose /dev/md3 --level=5 --raid-devices=3 /dev/sdd1 /dev/sde1 /dev/sdf1
mdadm: layout defaults to left-symmetric
mdadm: layout defaults to left-symmetric
mdadm: chunk size defaults to 512K
mdadm: size set to 3906885632K
mdadm: automatically enabling write-intent bitmap on large array
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md3 started.

and /proc/mdstat contained
md3 : active raid5 sdf1[3] sde1[1] sdd1[0]
      7813771264 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/2] [UU_]
      [>....................]  recovery =  0.1% (4734656/3906885632) finish=1030.1min speed=63128K/sec
      bitmap: 0/30 pages [0KB], 65536KB chunk

unused devices: <none>

which indicates that adding the parity should take about 17 hours.

About an hour later it said
 md3 : active raid5 sdf1[3] sde1[1] sdd1[0]
      7813771264 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/2] [UU_]
      [>....................]  recovery =  0.8% (33160860/3906885632) finish=346.9min speed=186077K/sec
      bitmap: 0/30 pages [0KB], 65536KB chunk

unused devices: <none>

And I thought that was going awfully fast.  Now, less than 3 hours later, it's saying
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md3 : active raid5 sde1[1] sdd1[0]
      7813771264 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/2] [UU_]
      bitmap: 2/30 pages [8KB], 65536KB chunk

unused devices: <none>

And you'd think that means the construction is done.  But wait a minute.  It only shows 2 drives, and  lsblk(8) says /dev/sdf1 is not part of the array.
NAME        MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
sda           8:0    0   1.8T  0 disk 
├─sda1        8:1    0     1M  0 part 
├─sda2        8:2    0    32G  0 part  /
├─sda3        8:3    0    32G  0 part 
├─sda4        8:4    0     1G  0 part 
├─sda5        8:5    0    96G  0 part  /vhome
├─sda6        8:6    0    64G  0 part  /var/www
├─sda7        8:7    0    32G  0 part  /vhome/kevin/VM
├─sda8        8:8    0 190.1G  0 part  /vhome/kevin/Projects
├─sda9        8:9    0     2G  0 part  [SWAP]
└─sda10       8:10   0   1.4T  0 part 
sdb           8:16   0 447.1G  0 disk 
├─sdb1        8:17   0   100M  0 part 
├─sdb2        8:18   0 446.6G  0 part 
└─sdb3        8:19   0   450M  0 part 
sdc           8:32   0   3.7T  0 disk 
├─sdc1        8:33   0     1M  0 part 
├─sdc2        8:34   0    32G  0 part  [SWAP]
├─sdc3        8:35   0    64G  0 part 
├─sdc4        8:36   0    32G  0 part  /vhome/kevin/hex
├─sdc5        8:37   0    32G  0 part  /vhome/kevin/hex/build
├─sdc6        8:38   0   192G  0 part 
├─sdc7        8:39   0    64G  0 part 
├─sdc8        8:40   0    32G  0 part 
├─sdc9        8:41   0    32G  0 part 
└─sdc10       8:42   0   3.2T  0 part  /tmp
sdd           8:48   0   3.7T  0 disk 
└─sdd1        8:49   0   3.7T  0 part 
  └─md3       9:3    0   7.3T  0 raid5
    └─md3p1 259:1    0   7.3T  0 md    /raid
sde           8:64   0   3.7T  0 disk 
└─sde1        8:65   0   3.7T  0 part 
  └─md3       9:3    0   7.3T  0 raid5
    └─md3p1 259:1    0   7.3T  0 md    /raid
sdf           8:80   0   3.7T  0 disk 
└─sdf1        8:81   0   3.7T  0 part 
sdg           8:96   0   1.8T  0 disk 
└─sdg1        8:97   0   1.8T  0 part 
sr0          11:0    1  1024M  0 rom  

Where did I go wrong?  What's happening here?  Does anybody know?

Why does mdstat show only 2 drives, but is not calling that an error since it's RAID-5?


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Kevin O'Gorman
#define QUESTION ((bb) || (!bb))   /* Shakespeare */

Please consider the environment before printing this email.


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Re: Trouble building a RAID 4 array with mdadm

Kevin O'Gorman
Never mind.  I think I'm having a mobo meltdown.  In any event, I'm seeing random errors on most of my hard drives, and some of them caused the RAID to go offline.

Clearly, I have to sort that out before I start blaming anything related to RAID.

On Sat, Apr 1, 2017 at 9:13 PM, Kevin O'Gorman <[hidden email]> wrote:
I'm on Xubuntu 16.04.2 LTS, using mdadm.  I've already built a RAID-1 array and had some success with it.  I'm trying to build a RAID 5 array, and having troubles.

I'm using the instructions I found on DigitalOcean (http://goo.gl/ZzwyxQ)

I did the mdadm --create, thus:
mdadm --create --verbose /dev/md3 --level=5 --raid-devices=3 /dev/sdd1 /dev/sde1 /dev/sdf1
mdadm: layout defaults to left-symmetric
mdadm: layout defaults to left-symmetric
mdadm: chunk size defaults to 512K
mdadm: size set to 3906885632K
mdadm: automatically enabling write-intent bitmap on large array
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md3 started.

and /proc/mdstat contained
md3 : active raid5 sdf1[3] sde1[1] sdd1[0]
      <a href="tel:(781)%20377-1264" value="+17813771264" target="_blank">7813771264 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/2] [UU_]
      [>....................]  recovery =  0.1% (4734656/3906885632) finish=1030.1min speed=63128K/sec
      bitmap: 0/30 pages [0KB], 65536KB chunk

unused devices: <none>

which indicates that adding the parity should take about 17 hours.

About an hour later it said
 md3 : active raid5 sdf1[3] sde1[1] sdd1[0]
      <a href="tel:(781)%20377-1264" value="+17813771264" target="_blank">7813771264 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/2] [UU_]
      [>....................]  recovery =  0.8% (33160860/3906885632) finish=346.9min speed=186077K/sec
      bitmap: 0/30 pages [0KB], 65536KB chunk

unused devices: <none>

And I thought that was going awfully fast.  Now, less than 3 hours later, it's saying
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md3 : active raid5 sde1[1] sdd1[0]
      <a href="tel:(781)%20377-1264" value="+17813771264" target="_blank">7813771264 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/2] [UU_]
      bitmap: 2/30 pages [8KB], 65536KB chunk

unused devices: <none>

And you'd think that means the construction is done.  But wait a minute.  It only shows 2 drives, and  lsblk(8) says /dev/sdf1 is not part of the array.
NAME        MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
sda           8:0    0   1.8T  0 disk 
├─sda1        8:1    0     1M  0 part 
├─sda2        8:2    0    32G  0 part  /
├─sda3        8:3    0    32G  0 part 
├─sda4        8:4    0     1G  0 part 
├─sda5        8:5    0    96G  0 part  /vhome
├─sda6        8:6    0    64G  0 part  /var/www
├─sda7        8:7    0    32G  0 part  /vhome/kevin/VM
├─sda8        8:8    0 190.1G  0 part  /vhome/kevin/Projects
├─sda9        8:9    0     2G  0 part  [SWAP]
└─sda10       8:10   0   1.4T  0 part 
sdb           8:16   0 447.1G  0 disk 
├─sdb1        8:17   0   100M  0 part 
├─sdb2        8:18   0 446.6G  0 part 
└─sdb3        8:19   0   450M  0 part 
sdc           8:32   0   3.7T  0 disk 
├─sdc1        8:33   0     1M  0 part 
├─sdc2        8:34   0    32G  0 part  [SWAP]
├─sdc3        8:35   0    64G  0 part 
├─sdc4        8:36   0    32G  0 part  /vhome/kevin/hex
├─sdc5        8:37   0    32G  0 part  /vhome/kevin/hex/build
├─sdc6        8:38   0   192G  0 part 
├─sdc7        8:39   0    64G  0 part 
├─sdc8        8:40   0    32G  0 part 
├─sdc9        8:41   0    32G  0 part 
└─sdc10       8:42   0   3.2T  0 part  /tmp
sdd           8:48   0   3.7T  0 disk 
└─sdd1        8:49   0   3.7T  0 part 
  └─md3       9:3    0   7.3T  0 raid5
    └─md3p1 259:1    0   7.3T  0 md    /raid
sde           8:64   0   3.7T  0 disk 
└─sde1        8:65   0   3.7T  0 part 
  └─md3       9:3    0   7.3T  0 raid5
    └─md3p1 259:1    0   7.3T  0 md    /raid
sdf           8:80   0   3.7T  0 disk 
└─sdf1        8:81   0   3.7T  0 part 
sdg           8:96   0   1.8T  0 disk 
└─sdg1        8:97   0   1.8T  0 part 
sr0          11:0    1  1024M  0 rom  

Where did I go wrong?  What's happening here?  Does anybody know?

Why does mdstat show only 2 drives, but is not calling that an error since it's RAID-5?


--
Kevin O'Gorman
#define QUESTION ((bb) || (!bb))   /* Shakespeare */

Please consider the environment before printing this email.




--
Kevin O'Gorman
#define QUESTION ((bb) || (!bb))   /* Shakespeare */

Please consider the environment before printing this email.


--
ubuntu-users mailing list
[hidden email]
Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-users
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