Trouble building a RAID 4 array with mdadm
Kevin O'Gorman
kogorman at gmail.com
Sun Apr 2 21:00:31 UTC 2017
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 <kogorman at gmail.com> 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]
> 7813771264 <(781)%20377-1264> 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 <(781)%20377-1264> 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 <(781)%20377-1264> 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.
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