LVM & RAID

Logical Volume 생성하기

# lvmdiskscan
  /dev/cl/root [      26.99 GiB]
  /dev/sda1    [     953.66 MiB]
  /dev/vda1    [       1.00 GiB]
  /dev/cl/swap [       2.00 GiB]
  /dev/sda2    [       2.07 GiB]
  /dev/vda2    [      29.00 GiB] LVM physical volume  #vm 기본 가상디스크
  /dev/sdb     [       3.00 GiB]
  /dev/sdc     [       3.00 GiB]
  4 disks
  3 partitions
  0 LVM physical volume whole disks
  1 LVM physical volume
# pvcreate /dev/sdb
  Physical volume "/dev/sdb" successfully created.
# pvcreate /dev/sdc
  Physical volume "/dev/sdc" successfully created.
# lvmdiskscan
  /dev/cl/root [      26.99 GiB]
  /dev/sda1    [     953.66 MiB]
  /dev/vda1    [       1.00 GiB]
  /dev/cl/swap [       2.00 GiB]
  /dev/sda2    [       2.07 GiB]
  /dev/vda2    [      29.00 GiB] LVM physical volume
  /dev/sdb     [       3.00 GiB] LVM physical volume
  /dev/sdc     [       3.00 GiB] LVM physical volume
  2 disks
  3 partitions
  2 LVM physical volume whole disks
  1 LVM physical volume
# vgcreate vgcolor /dev/sdb /dev/sdc
  Volume group "vgcolor" successfully created
# vgs
  VG      #PV #LV #SN Attr   VSize  VFree
  cl        1   2   0 wz--n- 29.00g 4.00m
  vgcolor   2   0   0 wz--n-  5.99g 5.99g

# pvs
  PV         VG      Fmt  Attr PSize  PFree
  /dev/sdb   vgcolor lvm2 a--   3.00g 3.00g
  /dev/sdc   vgcolor lvm2 a--   3.00g 3.00g
  /dev/vda2  cl      lvm2 a--  29.00g 4.00m
# lvcreate -L 2G -n lvred vgcolor
  Logical volume "lvred" created.
# lvs
  LV    VG      Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  root  cl      -wi-ao---- 26.99g                                                   
  swap  cl      -wi-ao----  2.00g                                                   
  lvred vgcolor -wi-a-----  2.00g                                                   
# vgs
  VG      #PV #LV #SN Attr   VSize  VFree
  cl        1   2   0 wz--n- 29.00g 4.00m
  vgcolor   2   1   0 wz--n-  5.99g 3.99g

# pvdisplay /dev/sdb
  --- Physical volume ---
  PV Name               /dev/sdb
  VG Name               vgcolor
  PV Size               3.00 GiB / not usable 4.00 MiB
  Allocatable           yes
  PE Size               4.00 MiB
  Total PE              767
  Free PE               255
  Allocated PE          512
  PV UUID               4R5def-1n3c-ohnl-Q1C0-JOL5-t0QJ-UKUqC6

# lvcreate -L 512M -n lvblue vgcolor
  Logical volume "lvblue" created.
# mkfs.xfs /dev/vgcolor/lvblue
meta-data=/dev/vgcolor/lvblue    isize=512    agcount=4, agsize=32768 blks
# mkdir /blue

# lvcreate -L 512M -n lvgreen vgcolor
  Logical volume "lvgreen" created.
# mkfs.ext4 /dev/vgcolor/lvgreen
mke2fs 1.42.9 (28-Dec-2013)
# mkdir /green
# vi /etc/fstab
... 생략 ...
/dev/vgcolor/lvgreen /green ext4    defaults    0    1
/dev/vgcolor/lvblue    /blue    xfs    default        0    1

# df -hT
Filesystem                  Type      Size  Used Avail Use% Mounted on
/dev/mapper/cl-root         xfs        27G  1.1G   26G   5% /
devtmpfs                    devtmpfs  909M     0  909M   0% /dev
tmpfs                       tmpfs     920M     0  920M   0% /dev/shm
tmpfs                       tmpfs     920M  8.5M  912M   1% /run
tmpfs                       tmpfs     920M     0  920M   0% /sys/fs/cgroup
/dev/sda1                   xfs       951M   34M  918M   4% /xfs
/dev/sda2                   ext4      2.0G  258M  1.7G  14% /yohan
/dev/vda1                   xfs      1014M  141M  874M  14% /boot
tmpfs                       tmpfs     184M     0  184M   0% /run/user/0
/dev/mapper/vgcolor-lvblue  xfs       509M   26M  483M   6% /blue
/dev/mapper/vgcolor-lvgreen ext4      488M  780K  452M   1% /green

# lvmdiskscan
  /dev/cl/root         [      26.99 GiB]
  /dev/sda1            [     953.66 MiB]
  /dev/vda1            [       1.00 GiB]
  /dev/cl/swap         [       2.00 GiB]
  /dev/sda2            [       2.07 GiB]
  /dev/vda2            [      29.00 GiB] LVM physical volume
  /dev/vgcolor/lvred   [       2.00 GiB]
  /dev/vgcolor/lvblue  [     512.00 MiB]
  /dev/vgcolor/lvgreen [     512.00 MiB]
  /dev/sdb             [       3.00 GiB] LVM physical volume
  /dev/sdc             [       3.00 GiB] LVM physical volume
  5 disks
  3 partitions
  2 LVM physical volume whole disks
  1 LVM physical volume

Exporting and Importing a VG

# 볼륨 그룹을 장치에서 떼낼 때 사용한다. OS에서 해당 디바이스를 사용하지 못하게 볼륨그룹을 export한다. 디스크 교체나 상대방에게 디스크를 떼내줄 때 export 까지 수행하면된다. 잘 됐는지 확인하려면 pvscan 명령어를 사용 할 수 있다.

# df -hT
Filesystem                  Type      Size  Used Avail Use% Mounted on
/dev/mapper/cl-root         xfs        27G  1.1G   26G   5% /
devtmpfs                    devtmpfs  909M     0  909M   0% /dev
tmpfs                       tmpfs     920M     0  920M   0% /dev/shm
tmpfs                       tmpfs     920M  8.5M  912M   1% /run
tmpfs                       tmpfs     920M     0  920M   0% /sys/fs/cgroup
/dev/sda1                   xfs       951M   38M  914M   4% /xfs
/dev/vda1                   xfs      1014M  141M  874M  14% /boot
/dev/sda2                   ext4      2.0G  258M  1.7G  14% /yohan
/dev/mapper/vgcolor-lvgreen ext4      488M  780K  452M   1% /green
/dev/mapper/vgcolor-lvblue  xfs       509M   26M  483M   6% /blue
tmpfs                       tmpfs     184M     0  184M   0% /run/user/0
# umount /green
# umount /blue
# vgchange -an vgcolor
  0 logical volume(s) in volume group "vgcolor" now active

# vgexport vgcolor
  Volume group "vgcolor" successfully exported
# pvscan
  PV /dev/vda2   VG cl              lvm2 [29.00 GiB / 4.00 MiB free]
  PV /dev/sdb     is in exported VG vgcolor [3.00 GiB / 508.00 MiB free]
  PV /dev/sdc     is in exported VG vgcolor [3.00 GiB / 2.50 GiB free]
  Total: 3 [34.99 GiB] / in use: 3 [34.99 GiB] / in no VG: 0 [0   ]

# 다시 OS에서 볼륨 그룹을 인식하고 싶으면 다음과 같이할 수 있다. 하고 난뒤 뗴낸 사람이랑 붙인사람이랑 /etc/fstab 도 정리해야한다.

# vgimport vgcolor
  Volume group "vgcolor" successfully imported
# vgchange -ay vgcolor
  3 logical volume(s) in volume group "vgcolor" now active
# mount -a
# df -hT
Filesystem                  Type      Size  Used Avail Use% Mounted on
/dev/mapper/cl-root         xfs        27G  1.1G   26G   5% /
devtmpfs                    devtmpfs  909M     0  909M   0% /dev
tmpfs                       tmpfs     920M     0  920M   0% /dev/shm
tmpfs                       tmpfs     920M  8.5M  912M   1% /run
tmpfs                       tmpfs     920M     0  920M   0% /sys/fs/cgroup
/dev/sda1                   xfs       951M   38M  914M   4% /xfs
/dev/vda1                   xfs      1014M  141M  874M  14% /boot
/dev/sda2                   ext4      2.0G  258M  1.7G  14% /yohan
tmpfs                       tmpfs     184M     0  184M   0% /run/user/0
/dev/mapper/vgcolor-lvblue  xfs       509M   26M  483M   6% /blue
/dev/mapper/vgcolor-lvgreen ext4      488M  780K  452M   1% /green

LVM 구성 보기

# pvdisplay, vgdisplay, lvdisplay 를 이용하여 볼 수 있다. pvs, vgs, lvs 를 이용하여 포맷을 정해서 출력할 수 있다. 아래는 lvs 사용법이다.

# lvs -o lv_name,lv_size,devices
  LV      LSize   Devices      
  root     26.99g /dev/vda2(512)
  swap      2.00g /dev/vda2(0) 
  lvblue  512.00m /dev/sdb(512)
  lvgreen 512.00m /dev/sdc(0)  
  lvred     2.00g /dev/sdb(0)
# lvs -o help
  Logical Volume Fields
  ---------------------
    lv_all                 - All fields in this section.
    lv_uuid                - Unique identifier.
    lv_name                - Name.  LVs created for internal use are enclosed in brackets.
... 생략 ...
# vgdisplay
  --- Volume group ---
  VG Name               cl
  System ID            
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  3
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
... 생략 ...
  --- Volume group ---
  VG Name               vgcolor
  System ID            
... 생략...

# lvdisplay /dev/vgcolor
  --- Logical volume ---
  LV Path                /dev/vgcolor/lvred
  LV Name                lvred
  VG Name                vgcolor
  LV UUID                87yEQT-2AiY-68dt-8XH7-mX9w-mqE0-JHTcZe
....
  --- Logical volume ---
  LV Path                /dev/vgcolor/lvblue
  LV Name                lvblue
  VG Name                vgcolor
  LV UUID                RrB5LH-skdZ-ty5n-c1jc-rTo5-O52q-j07RSF
.....
  --- Logical volume ---
  LV Path                /dev/vgcolor/lvgreen
  LV Name                lvgreen
  VG Name                vgcolor
  LV UUID                cQvoUp-EfDB-9GEy-RcHC-vZ8G-aaIs-OpztYx
  LV Write Access        read/write
....

새 디스크를 volume group에 추가하고 logical volume에 추가하기. 또 logical volume 용량 줄여보기.

# 우선 기존상태를 확인해보았다.

# vgs
  VG      #PV #LV #SN Attr   VSize  VFree
  cl        1   2   0 wz--n- 29.00g 4.00m
  vgcolor   2   3   0 wz--n-  5.99g 2.99g
# lsscsi
[2:0:0:1]    disk    QEMU     QEMU HARDDISK    1.5.  /dev/sdc
[2:0:0:2]    disk    QEMU     QEMU HARDDISK    1.5.  /dev/sdb
[2:0:0:3]    disk    QEMU     QEMU HARDDISK    1.5.  /dev/sda
# pvs
  PV         VG      Fmt  Attr PSize  PFree 
  /dev/sdb   vgcolor lvm2 a--   3.00g 508.00m
  /dev/sdc   vgcolor lvm2 a--   3.00g   2.50g
  /dev/vda2  cl      lvm2 a--  29.00g   4.00m

# 새로 디스크를 추가하고 volume group에 추가한다. volume group이 확장된다. 그뒤 확인해보자.

# lsscsi
[2:0:0:1]    disk    QEMU     QEMU HARDDISK    1.5.  /dev/sdc
[2:0:0:2]    disk    QEMU     QEMU HARDDISK    1.5.  /dev/sdb
[2:0:0:3]    disk    QEMU     QEMU HARDDISK    1.5.  /dev/sda
[2:0:0:4]    disk    QEMU     QEMU HARDDISK    1.5.  /dev/sdd
# vgextend vgcolor /dev/sdd
  Volume group "vgcolor" successfully extended
# vgs
  VG      #PV #LV #SN Attr   VSize  VFree
  cl        1   2   0 wz--n- 29.00g 4.00m
  vgcolor   3   3   0 wz--n-  8.99g 5.99g
# pvs
  PV         VG      Fmt  Attr PSize  PFree 
  /dev/sdb   vgcolor lvm2 a--   3.00g 508.00m
  /dev/sdc   vgcolor lvm2 a--   3.00g   2.50g
  /dev/sdd   vgcolor lvm2 a--   3.00g   3.00g
  /dev/vda2  cl      lvm2 a--  29.00g   4.00m

# 이제 logical volume에 추가해보자.

# lvextend -L 1G /dev/vgcolor/lvgreen
  Size of logical volume vgcolor/lvgreen changed from 512.00 MiB (128 extents) to 1.00 GiB (256 extents).
  Logical volume vgcolor/lvgreen successfully resized.
# df -hT |grep "green"
/dev/mapper/vgcolor-lvgreen ext4      488M  780K  452M   1% /green
# resize2fs /dev/vgcolor/lvgreen
resize2fs 1.42.9 (28-Dec-2013)
Filesystem at /dev/vgcolor/lvgreen is mounted on /green; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 1
The filesystem on /dev/vgcolor/lvgreen is now 262144 blocks long.

# df -hT |grep "green"
/dev/mapper/vgcolor-lvgreen ext4      992M  1.3M  935M   1% /green

# 로지컬 볼륨 green을 다시 리사이징 해보겠다. 디스크 체크를 우선적으로 해야한다.

# resize2fs /dev/vgcolor/lvgreen 512M
resize2fs 1.42.9 (28-Dec-2013)
Please run 'e2fsck -f /dev/vgcolor/lvgreen' first.

# e2fsck -f /dev/vgcolor/lvgreen
e2fsck 1.42.9 (28-Dec-2013)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/vgcolor/lvgreen: 11/65536 files (0.0% non-contiguous), 8539/262144 blocks

# resize2fs /dev/vgcolor/lvgreen 512M
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/vgcolor/lvgreen to 131072 (4k) blocks.
The filesystem on /dev/vgcolor/lvgreen is now 131072 blocks long.

# lvs
  LV      VG      Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  root    cl      -wi-ao----  26.99g                                                   
  swap    cl      -wi-ao----   2.00g                                                   
  lvblue  vgcolor -wi-ao---- 512.00m                                                   
  lvgreen vgcolor -wi-a-----   1.00g                                                   
  lvred   vgcolor -wi-a-----   2.00g                                                   
# lvreduce -L 512M /dev/vgcolor/lvgreen
  WARNING: Reducing active logical volume to 512.00 MiB.
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce vgcolor/lvgreen? [y/n]: y
  Size of logical volume vgcolor/lvgreen changed from 1.00 GiB (256 extents) to 512.00 MiB (128 extents).
  Logical volume vgcolor/lvgreen successfully resized.
# mount /green
# df -hT | grep "green"
/dev/mapper/vgcolor-lvgreen ext4      488M  780K  454M   1% /green
# lvs
  LV      VG      Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  root    cl      -wi-ao----  26.99g                                                   
  swap    cl      -wi-ao----   2.00g                                                   
  lvblue  vgcolor -wi-ao---- 512.00m                                                   
  lvgreen vgcolor -wi-ao---- 512.00m                                                   
  lvred   vgcolor -wi-a-----   2.00g       

# 로지컬 볼륨 blue를 확장해보겠다.

# lvextend -L 1G /dev/vgcolor/lvblue
  Size of logical volume vgcolor/lvblue changed from 512.00 MiB (128 extents) to 1.00 GiB (256 extents).
  Logical volume vgcolor/lvblue successfully resized.
# xfs_growfs /blue
meta-data=/dev/mapper/vgcolor-lvblue isize=512    agcount=4, agsize=32768 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0 spinodes=0
data     =                       bsize=4096   blocks=131072, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal               bsize=4096   blocks=855, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 131072 to 262144
# df -hT | grep "blue"
/dev/mapper/vgcolor-lvblue  xfs      1021M   26M  995M   3% /blue

이론 수업 : page 6-10 ~ 6-12 참고 device work ={ linear, strip (=parallelize), mirror... }

스냅샷  찍기

# ls /blue
# cp /etc/*.conf /blue
# ls /blue
asound.conf   GeoIP.conf  libaudit.conf   mke2fs.conf    sudo.conf       yum.conf
chrony.conf   host.conf   libuser.conf    nsswitch.conf  sudo-ldap.conf
dnsmasq.conf  kdump.conf  locale.conf     resolv.conf    sysctl.conf
dracut.conf   krb5.conf   logrotate.conf  rsyslog.conf   tcsd.conf
e2fsck.conf   ld.so.conf  man_db.conf     sestatus.conf  vconsole.conf

# lvcreate -s -L 256M -n snap1 /dev/vgcolor/lvblue
  Using default stripesize 64.00 KiB.
  Logical volume "snap1" created.
# lsblk -f
NAME                  FSTYPE   LABEL    UUID                                   MOUNTPOINT
sda                                                                           
├─sda1                xfs      XFS_yohan
                                        e4ece575-d12d-4ba2-91f5-50875d1fae68   /xfs
└─sda2                ext4     FS_ext4  8c876288-69bb-47e6-8dfa-04a33bdd35e9   /yohan
sdb                   LVM2_mem          4R5def-1n3c-ohnl-Q1C0-JOL5-t0QJ-UKUqC6
├─vgcolor-lvred                                                               
└─vgcolor-lvblue-real                                                         
  ├─vgcolor-lvblue    xfs               1a6e0741-e4a3-4c8a-a067-efc4a8df6dc6   /blue
  └─vgcolor-snap1     xfs               1a6e0741-e4a3-4c8a-a067-efc4a8df6dc6  
sdc                   LVM2_mem          qtOBMI-T4YC-5k2t-aTPI-UW3M-IUON-RfEzYC
├─vgcolor-lvgreen     ext4              d2734656-b417-406a-9a40-2ae5f481c539   /green
├─vgcolor-lvblue-real                                                         
│ ├─vgcolor-lvblue    xfs               1a6e0741-e4a3-4c8a-a067-efc4a8df6dc6   /blue
│ └─vgcolor-snap1     xfs               1a6e0741-e4a3-4c8a-a067-efc4a8df6dc6  
└─vgcolor-snap1-cow                                                           
  └─vgcolor-snap1     xfs               1a6e0741-e4a3-4c8a-a067-efc4a8df6dc6  
sdd                   LVM2_mem          1cmUCb-HQgC-pqux-6U6A-QdoV-HK7f-dw2A4C
vda                                                                           
├─vda1                xfs               372ce9fb-1903-4c73-8316-7cf9a50358fc   /boot
└─vda2                LVM2_mem          RZ8k6v-wAFn-q1tH-iEng-tZii-OCw3-uim3Z2
  ├─cl-root           xfs               7618555f-1b64-453d-8ce3-42f14d58e395   /
  └─cl-swap           swap              121e58e2-8f0d-40b0-9591-9d7bb5b2e56a   [SWAP]

# lvs
  LV      VG      Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  root    cl      -wi-ao----  26.99g                                                   
  swap    cl      -wi-ao----   2.00g                                                   
  lvblue  vgcolor owi-aos---   1.00g                                                   
  lvgreen vgcolor -wi-ao---- 512.00m                                                   
  lvred   vgcolor -wi-a-----   2.00g                                                   
  snap1   vgcolor swi-a-s--- 256.00m      lvblue 0.01                                

# 이제 백업을 해보자. 로지컬 볼륨 lvblue를 언마운트 하지 않는다면, uuid가 같은 볼륨이 존재하므로 백업이 안된다. no uuid 옵션을 사용할 수 있다.

# mkdir /backup
# ll /dev/vgcolor/snap1
lrwxrwxrwx. 1 root root 7 Jul 20 11:40 /dev/vgcolor/snap1 -> ../dm-7
# mount /dev/vgcolor/snap1 /backup
mount: wrong fs type, bad option, bad superblock on /dev/mapper/vgcolor-snap1,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.

# mount -o nouuid /dev/vgcolor/snap1 /backup
# ls /backup
asound.conf   GeoIP.conf  libaudit.conf   mke2fs.conf    sudo.conf       yum.conf
chrony.conf   host.conf   libuser.conf    nsswitch.conf  sudo-ldap.conf
dnsmasq.conf  kdump.conf  locale.conf     resolv.conf    sysctl.conf
dracut.conf   krb5.conf   logrotate.conf  rsyslog.conf   tcsd.conf
e2fsck.conf   ld.so.conf  man_db.conf     sestatus.conf  vconsole.conf
# ls /blue
asound.conf   GeoIP.conf  libaudit.conf   mke2fs.conf    sudo.conf       yum.conf
chrony.conf   host.conf   libuser.conf    nsswitch.conf  sudo-ldap.conf
dnsmasq.conf  kdump.conf  locale.conf     resolv.conf    sysctl.conf
dracut.conf   krb5.conf   logrotate.conf  rsyslog.conf   tcsd.conf
e2fsck.conf   ld.so.conf  man_db.conf     sestatus.conf  vconsole.conf

# df -hT
Filesystem                  Type      Size  Used Avail Use% Mounted on
/dev/mapper/cl-root         xfs        27G  1.1G   26G   5% /
devtmpfs                    devtmpfs  909M     0  909M   0% /dev
tmpfs                       tmpfs     920M     0  920M   0% /dev/shm
tmpfs                       tmpfs     920M  8.5M  912M   1% /run
tmpfs                       tmpfs     920M     0  920M   0% /sys/fs/cgroup
/dev/vda1                   xfs      1014M  138M  877M  14% /boot
/dev/sda1                   xfs       951M   38M  914M   4% /xfs
/dev/sda2                   ext4      2.0G  258M  1.7G  14% /yohan
/dev/mapper/vgcolor-lvblue  xfs      1021M   27M  995M   3% /blue
tmpfs                       tmpfs     184M     0  184M   0% /run/user/0
/dev/mapper/vgcolor-lvgreen ext4      488M  780K  454M   1% /green
/dev/mapper/vgcolor-snap1   xfs      1021M   33M  989M   4% /backup
# lsblk -f
NAME                  FSTYPE   LABEL    UUID                                   MOUNTPOINT
sda                                                                           
├─sda1                xfs      XFS_yohan
                                        e4ece575-d12d-4ba2-91f5-50875d1fae68   /xfs
└─sda2                ext4     FS_ext4  8c876288-69bb-47e6-8dfa-04a33bdd35e9   /yohan
sdb                   LVM2_mem          4R5def-1n3c-ohnl-Q1C0-JOL5-t0QJ-UKUqC6
├─vgcolor-lvred                                                               
└─vgcolor-lvblue-real                                                         
  ├─vgcolor-lvblue    xfs               1a6e0741-e4a3-4c8a-a067-efc4a8df6dc6   /blue
  └─vgcolor-snap1     xfs               1a6e0741-e4a3-4c8a-a067-efc4a8df6dc6   /backup
sdc                   LVM2_mem          qtOBMI-T4YC-5k2t-aTPI-UW3M-IUON-RfEzYC
├─vgcolor-lvgreen     ext4              d2734656-b417-406a-9a40-2ae5f481c539   /green
├─vgcolor-lvblue-real                                                         
│ ├─vgcolor-lvblue    xfs               1a6e0741-e4a3-4c8a-a067-efc4a8df6dc6   /blue
│ └─vgcolor-snap1     xfs               1a6e0741-e4a3-4c8a-a067-efc4a8df6dc6   /backup
└─vgcolor-snap1-cow                                                           
  └─vgcolor-snap1     xfs               1a6e0741-e4a3-4c8a-a067-efc4a8df6dc6   /backup
sdd                   LVM2_mem          1cmUCb-HQgC-pqux-6U6A-QdoV-HK7f-dw2A4C
vda                                                                           
├─vda1                xfs               372ce9fb-1903-4c73-8316-7cf9a50358fc   /boot
└─vda2                LVM2_mem          RZ8k6v-wAFn-q1tH-iEng-tZii-OCw3-uim3Z2
  ├─cl-root           xfs               7618555f-1b64-453d-8ce3-42f14d58e395   /
  └─cl-swap           swap              121e58e2-8f0d-40b0-9591-9d7bb5b2e56a   [SWAP]
# umount /backup

# 기존 로지컬볼륨의 내용을 삭제하고 lvconvert --merge 로 로지컬 볼륨을 복구한다.

# rm -rf /blue/*
# lvs
  LV      VG      Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  root    cl      -wi-ao----  26.99g                                                   
  swap    cl      -wi-ao----   2.00g                                                   
  lvblue  vgcolor owi-aos---   1.00g                                                   
  lvgreen vgcolor -wi-ao---- 512.00m                                                   
  lvred   vgcolor -wi-a-----   2.00g                                                   
  snap1   vgcolor swi-a-s--- 256.00m      lvblue 0.79  

# umount /blue
# lvconvert --merge /dev/vgcolor/snap1
  Merging of volume vgcolor/snap1 started.
  lvblue: Merged: 100.00%
# mount /blue
# ls /blue
asound.conf   GeoIP.conf  libaudit.conf   mke2fs.conf    sudo.conf       yum.conf
chrony.conf   host.conf   libuser.conf    nsswitch.conf  sudo-ldap.conf
dnsmasq.conf  kdump.conf  locale.conf     resolv.conf    sysctl.conf
dracut.conf   krb5.conf   logrotate.conf  rsyslog.conf   tcsd.conf
e2fsck.conf   ld.so.conf  man_db.conf     sestatus.conf  vconsole.conf

RAID  자세한 이론내용은 교재 6-19 참고

# 여러 physical device를 하나의 논리적 device로 바꿔준다. lv 와 비슷한듯.

Linear RAID
RAID-0 : stripe
RAID-1 : mirror (복구가능함, 가용률 50%)
RAID-1+0 : mirror, stripe (복구와 쓰기 속도 늘림, 가용률 50%)
RAD-3,4 : stripe, parity (복구를 위한 xor연산, 디스크가 늘수록 디스크 가용률 이 좋음)
RAID-5 : stripe, distributed parity 복구를 위한 xor연산)
RAID-6 : stripe, dual parity