QUESTION:
CentOS 7 does not boot after we extend a Volume Group (VG) over RAID 1 using another RAID 1. The process we use is demonstrated in PROCEDURE: Extend LVM ("root", "/") over RAID 1. What is wrong and/or missing in the process we demonstrate?
CONTEXT:
We are trying to extend a Volume Group (VG) over two RAID 1 (software) disks using two other RAID 1 (software) disks.
PROBLEM:
CentOS 7 does not start after we extend a VG (Volume Group).
PROCEDURE: Extend LVM ("root", "/") over RAID 1
- Format hard drives
Run the following 2 commands to make new MBR partition table on the two added hard drives...
parted /dev/sdc mklabel msdos
parted /dev/sdd mklabel msdos
Reload "fstab"...
mount -a
Use the fdisk command to create a new partition on each drive and format them as a Linux raid autodetect file system. First do this on /dev/sdc.
fdisk /dev/sdc
Follow these instructions...
- Type "n" to create a new partition;
- Type "p" to select primary partition;
- Type "1" to create /dev/sdb1;
- Press Enter to choose the default first sector;
- Press Enter to choose the default last sector. This partition will span across the entire drive;
- Type "t" and Enter "fd" to set partition type to Linux raid autodetect;
- Type "w" to apply the above changes.
NOTE: Follow the same instruction to create a Linux raid autodetect partition on "/dev/sdd".
Now we have two raid devices "/dev/sdc1" and "/dev/sdd1".
- Create RAID 1 logical drive
Execute the following command to create RAID 1...
[root@localhost ~]# mdadm --create /dev/md125 --homehost=localhost --name=pv01 --level=mirror --bitmap=internal --consistency-policy=bitmap --raid-devices=2 /dev/sdc1 /dev/sdd1
mdadm: Note: this array has metadata at the start and
may not be suitable as a boot device. If you plan to
store '/boot' on this device please ensure that
your boot-loader understands md/v1.x metadata, or use
--metadata=0.90
Continue creating array? y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md125 started.
Increasing the logical volume
[root@localhost ~]# pvcreate /dev/md125
Physical volume "/dev/md125" successfully created.
We extend the "centosvg" volume group by adding in the physical volume of "/dev/md125" ("RAID 1") which we created using the "pvcreate" command just before...
[root@localhost ~]# vgextend centosvg /dev/md125
Volume group "centosvg" successfully extended
Increase the logical volume with the "lvextend" command - will be taking our original logical volume and extending it over our new disk/partition/physical ("RAID 1") volume of "/dev/md125"...
[root@localhost ~]# lvextend /dev/centosvg/root /dev/md125
Size of logical volume centosvg/root changed from 4.95 GiB (1268 extents) to <12.95 GiB (3314 extents).
Logical volume centosvg/root successfully resized.
Resize the file system using the "xfs_growfs" command in order to make use of this space...
[root@localhost ~]# xfs_growfs /dev/centosvg/root
meta-data=/dev/mapper/centosvg-root isize=512 agcount=4, agsize=324608 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=1298432, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 1298432 to 3393536
- Save our RAID1 configuration
This command updates your boot kernel configuration to match the current state of your system...
mdadm --detail --scan > /tmp/mdadm.conf
\cp -v /tmp/mdadm.conf /etc/mdadm.conf
Update GRUB configuration so that it knows about the new devices...
grub2-mkconfig -o "$(readlink -e /etc/grub2.cfg)"
You should run the following command to generate a new "initramfs" image after running the above command...
dracut -fv
ERROR:
INFRASTRUCTURE/OTHER INFORMATION:
lsblk
[root@localhost ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 8G 0 disk
├─sda1 8:1 0 1G 0 part
│ └─md127 9:127 0 1023M 0 raid1 /boot
└─sda2 8:2 0 7G 0 part
└─md126 9:126 0 7G 0 raid1
├─centosvg-root 253:0 0 5G 0 lvm /
└─centosvg-swap 253:1 0 2G 0 lvm [SWAP]
sdb 8:16 0 8G 0 disk
├─sdb1 8:17 0 1G 0 part
│ └─md127 9:127 0 1023M 0 raid1 /boot
└─sdb2 8:18 0 7G 0 part
└─md126 9:126 0 7G 0 raid1
├─centosvg-root 253:0 0 5G 0 lvm /
└─centosvg-swap 253:1 0 2G 0 lvm [SWAP]
sdc 8:32 0 8G 0 disk
sdd 8:48 0 8G 0 disk
sr0 11:0 1 1024M 0 rom
mdadm --examine /dev/sdc /dev/sdd
[root@localhost ~]# mdadm --examine /dev/sdc /dev/sdd
/dev/sdc:
MBR Magic : aa55
Partition[0] : 16775168 sectors at 2048 (type fd)
/dev/sdd:
MBR Magic : aa55
Partition[0] : 16775168 sectors at 2048 (type fd)
mdadm --examine /dev/sdc1 /dev/sdd1
[root@localhost ~]# mdadm --examine /dev/sdc1 /dev/sdd1
/dev/sdc1:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x1
Array UUID : 51a622a9:666c7936:1bf1db43:8029ab06
Name : localhost:pv01
Creation Time : Tue Jan 7 13:42:20 2020
Raid Level : raid1
Raid Devices : 2
Avail Dev Size : 16764928 sectors (7.99 GiB 8.58 GB)
Array Size : 8382464 KiB (7.99 GiB 8.58 GB)
Data Offset : 10240 sectors
Super Offset : 8 sectors
Unused Space : before=10160 sectors, after=0 sectors
State : clean
Device UUID : f95b50e3:eed41b52:947ddbb4:b42a40d6
Internal Bitmap : 8 sectors from superblock
Update Time : Tue Jan 7 13:43:15 2020
Bad Block Log : 512 entries available at offset 16 sectors
Checksum : 9d4c040c - correct
Events : 25
Device Role : Active device 0
Array State : AA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdd1:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x1
Array UUID : 51a622a9:666c7936:1bf1db43:8029ab06
Name : localhost:pv01
Creation Time : Tue Jan 7 13:42:20 2020
Raid Level : raid1
Raid Devices : 2
Avail Dev Size : 16764928 sectors (7.99 GiB 8.58 GB)
Array Size : 8382464 KiB (7.99 GiB 8.58 GB)
Data Offset : 10240 sectors
Super Offset : 8 sectors
Unused Space : before=10160 sectors, after=0 sectors
State : clean
Device UUID : bcb18234:aab93a6c:80384b09:c547fdb9
Internal Bitmap : 8 sectors from superblock
Update Time : Tue Jan 7 13:43:15 2020
Bad Block Log : 512 entries available at offset 16 sectors
Checksum : 40ca1688 - correct
Events : 25
Device Role : Active device 1
Array State : AA ('A' == active, '.' == missing, 'R' == replacing)
cat /proc/mdstat
[root@localhost ~]# cat /proc/mdstat
Personalities : [raid1]
md125 : active raid1 sdd1[1] sdc1[0]
8382464 blocks super 1.2 [2/2] [UU]
bitmap: 0/1 pages [0KB], 65536KB chunk
md126 : active raid1 sda2[0] sdb2[1]
7332864 blocks super 1.2 [2/2] [UU]
bitmap: 0/1 pages [0KB], 65536KB chunk
md127 : active raid1 sda1[0] sdb1[1]
1047552 blocks super 1.2 [2/2] [UU]
bitmap: 0/1 pages [0KB], 65536KB chunk
unused devices: <none>
mdadm --detail /dev/md125
[root@localhost ~]# mdadm --detail /dev/md125
/dev/md125:
Version : 1.2
Creation Time : Tue Jan 7 13:42:20 2020
Raid Level : raid1
Array Size : 8382464 (7.99 GiB 8.58 GB)
Used Dev Size : 8382464 (7.99 GiB 8.58 GB)
Raid Devices : 2
Total Devices : 2
Persistence : Superblock is persistent
Intent Bitmap : Internal
Update Time : Tue Jan 7 13:43:15 2020
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Consistency Policy : bitmap
Name : localhost:pv01
UUID : 51a622a9:666c7936:1bf1db43:8029ab06
Events : 25
Number Major Minor RaidDevice State
0 8 33 0 active sync /dev/sdc1
1 8 49 1 active sync /dev/sdd1
fdisk -l
[root@localhost ~]# fdisk -l
Disk /dev/sda: 8589 MB, 8589934592 bytes, 16777216 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000f2ab2
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 2101247 1049600 fd Linux raid autodetect
/dev/sda2 2101248 16777215 7337984 fd Linux raid autodetect
Disk /dev/sdb: 8589 MB, 8589934592 bytes, 16777216 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x0002519d
Device Boot Start End Blocks Id System
/dev/sdb1 * 2048 2101247 1049600 fd Linux raid autodetect
/dev/sdb2 2101248 16777215 7337984 fd Linux raid autodetect
Disk /dev/sdc: 8589 MB, 8589934592 bytes, 16777216 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x0007bd31
Device Boot Start End Blocks Id System
/dev/sdc1 2048 16777215 8387584 fd Linux raid autodetect
Disk /dev/sdd: 8589 MB, 8589934592 bytes, 16777216 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x00086fef
Device Boot Start End Blocks Id System
/dev/sdd1 2048 16777215 8387584 fd Linux raid autodetect
Disk /dev/md127: 1072 MB, 1072693248 bytes, 2095104 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/md126: 7508 MB, 7508852736 bytes, 14665728 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/centosvg-root: 5318 MB, 5318377472 bytes, 10387456 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/centosvg-swap: 2147 MB, 2147483648 bytes, 4194304 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/md125: 8583 MB, 8583643136 bytes, 16764928 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
df -h
[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 484M 0 484M 0% /dev
tmpfs 496M 0 496M 0% /dev/shm
tmpfs 496M 6.8M 489M 2% /run
tmpfs 496M 0 496M 0% /sys/fs/cgroup
/dev/mapper/centosvg-root 5.0G 1.4G 3.7G 27% /
/dev/md127 1020M 164M 857M 17% /boot
tmpfs 100M 0 100M 0% /run/user/0
vgdisplay
[root@localhost ~]# vgdisplay
--- Volume group ---
VG Name centosvg
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 1
Act PV 1
VG Size 6.99 GiB
PE Size 4.00 MiB
Total PE 1790
Alloc PE / Size 1780 / 6.95 GiB
Free PE / Size 10 / 40.00 MiB
VG UUID 6mKxWb-KOIe-fW1h-zukQ-f7aJ-vxD5-hKAaZG
pvscan
[root@localhost ~]# pvscan
PV /dev/md126 VG centosvg lvm2 [6.99 GiB / 40.00 MiB free]
PV /dev/md125 VG centosvg lvm2 [7.99 GiB / 7.99 GiB free]
Total: 2 [14.98 GiB] / in use: 2 [14.98 GiB] / in no VG: 0 [0 ]
lvdisplay
[root@localhost ~]# lvdisplay
--- Logical volume ---
LV Path /dev/centosvg/swap
LV Name swap
VG Name centosvg
LV UUID o5G6gj-1duf-xIRL-JHoO-ux2f-6oQ8-LIhdtA
LV Write Access read/write
LV Creation host, time localhost, 2020-01-06 13:22:08 -0500
LV Status available
# open 2
LV Size 2.00 GiB
Current LE 512
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:1
--- Logical volume ---
LV Path /dev/centosvg/root
LV Name root
VG Name centosvg
LV UUID GTbGaF-Wh4J-1zL3-H7r8-p5YZ-kn9F-ayrX8U
LV Write Access read/write
LV Creation host, time localhost, 2020-01-06 13:22:09 -0500
LV Status available
# open 1
LV Size 4.95 GiB
Current LE 1268
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:0
cat /run/initramfs/rdsosreport.txt
Thank you! =D
[Refs.: https://4fasters.com.br/2017/11/12/lpic-2-o-que-e-e-para-que-serve-o-dracut/ , https://unix.stackexchange.com/a/152249/61742 , https://www.howtoforge.com/set-up-raid1-on-a-running-lvm-system-debian-etch-p2 , https://www.howtoforge.com/setting-up-lvm-on-top-of-software-raid1-rhel-fedora , https://www.linuxbabe.com/linux-server/linux-software-raid-1-setup , https://www.rootusers.com/how-to-increase-the-size-of-a-linux-lvm-by-adding-a-new-disk/ ]
