Restore Data Using DiskSafe for CentOS
Steps on how to Restore Data Using DiskSafe for CentOS
Refer to Protect CentOS with DiskSafe Agent to configure backup for CentOS prior continue for the restoration steps below
List all available snapshots and record the timestamp of 1584723025 (Snapshot 2)
[root@checkmk /]# dscli snapshot list sda
All snapshots of sda
Snapshot 1:
Snapshot Timestamp = 1584719577(2020/03/20 23:52:57)
Snapshot Blocks Count = 18835968
Mounted = NO
Snapshot 2:
Snapshot Timestamp = 1584723025(2020/03/21 00:50:25)
Snapshot Blocks Count = 12251136
Mounted = NO
Snapshot with Timestamp=1584723025 is mounted as /dev/sdd
[root@checkmk /]# dscli snapshot mount sda timestamp=1584723025
Mount snapshot with timestamp 1584723025 of sda
Snapshot mounted, get the information...
Snapshot device name: /dev/sdd
Command succeeded
How to Restore Data using DiskSafe for CentOS from Snapshot
It is strongly recommended to study Beginner’s Guide to LVM (Logical Volume Management) to understand how Logical Volume Management (LVM) works before continue the steps below
Add Modify the /etc/lvm/lvm.conf file to include "a|^/dev/sdd2$|” in global_Filter to make the new /dev/sdd (Snapshot Disk) detected by system
vi /etc/lvm/lvm.conf
global_filter = [ "a|^/dev/disksafe/sda$|", "a|^/dev/disksafe/sda2$|", "a|^/dev/sdd2$|", "r|.*/|" ]
/dev/sdd (Snapshot Disk) is detected as duplicate PV with the original /dev/sda
[root@checkmk /]# vgscan
WARNING: found device with duplicate /dev/sdd2
WARNING: Disabling lvmetad cache which does not support duplicate PVs.
WARNING: Scan found duplicate PVs.
WARNING: Not using lvmetad because cache update failed.
Reading all physical volumes. This may take a while...
WARNING: Not using device /dev/sdd2 for PV H1ADa4-G7KT-h3MR-O8as-TEv3-368I-y77wVr.
WARNING: PV H1ADa4-G7KT-h3MR-O8as-TEv3-368I-y77wVr prefers device /dev/disksafe/sda2 because of previ ous preference.
Found volume group "centos" using metadata type lvm2
[root@checkmk /]# pvdisplay
WARNING: Not using lvmetad because duplicate PVs were found.
WARNING: Use multipath or vgimportclone to resolve duplicate PVs?
WARNING: After duplicates are resolved, run "pvscan --cache" to enable lvmetad.
WARNING: Not using device /dev/sdd2 for PV H1ADa4-G7KT-h3MR-O8as-TEv3-368I-y77wVr.
WARNING: PV H1ADa4-G7KT-h3MR-O8as-TEv3-368I-y77wVr prefers device /dev/disksafe/sda2 because device is used by LV.
--- Physical volume ---
PV Name /dev/disksafe/sda2
VG Name centos
PV Size <9.00 GiB / not usable 3.00 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 2303
Free PE 0
Allocated PE 2303
PV UUID H1ADa4-G7KT-h3MR-O8as-TEv3-368I-y77wVr
Resolve the duplicate PV issue with vgimportclone
[root@checkmk /]# vgimportclone /dev/sdd2
WARNING: Not using device /dev/sdd2 for PV H1ADa4-G7KT-h3MR-O8as-TEv3-368I-y77wVr.
WARNING: PV H1ADa4-G7KT-h3MR-O8as-TEv3-368I-y77wVr prefers device /dev/disksafe/sda2 because device i s used by LV.
[root@checkmk /]# vgimportclone /dev/sdd2
[root@checkmk /]# pvdisplay
--- Physical volume ---
PV Name /dev/disksafe/sda2
VG Name centos
PV Size <9.00 GiB / not usable 3.00 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 2303
Free PE 0
Allocated PE 2303
PV UUID H1ADa4-G7KT-h3MR-O8as-TEv3-368I-y77wVr
--- Physical volume ---
PV Name /dev/sdd2
VG Name centos11
PV Size <9.00 GiB / not usable 3.00 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 2303
Free PE 0
Allocated PE 2303
PV UUID AkVEuf-8I4B-Rsl4-JPo9-WMt0-3fev-fjq8uZ
Rescan the VG & LV
[root@checkmk /]# vgscan
Reading volume groups from cache.
Found volume group "centos" using metadata type lvm2
Found volume group "centos11" using metadata type lvm2
[root@checkmk /]# lvscan
ACTIVE '/dev/centos/swap' [1.00 GiB] inherit
ACTIVE '/dev/centos/root' [<8.00 GiB] inherit
inactive '/dev/centos11/swap' [1.00 GiB] inherit
inactive '/dev/centos11/root' [<8.00 GiB] inherit
Activate the Logical Volume (LV) that we are going to mount later
[root@checkmk /]# lvchange -ay /dev/centos11/root
[root@checkmk /]# lvscan
ACTIVE '/dev/centos/swap' [1.00 GiB] inherit
ACTIVE '/dev/centos/root' [<8.00 GiB] inherit
inactive '/dev/centos11/swap' [1.00 GiB] inherit
ACTIVE '/dev/centos11/root' [<8.00 GiB] inherit
Trying to mount the new Logical Volume (/dev/centos11/root) and get the duplicate UUID error below
[root@checkmk lvm]# mount /dev/centos11/root /mnt
mount: wrong fs type, bad option, bad superblock on /dev/mapper/centos11-root,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so.
[root@checkmk]dmesg
[10811.766108] XFS (dm-4): Filesystem has duplicate UUID 0623d025-0721-419a-8ce2-e8e9adc318d3
Mount the volume without UUID specified
[root@checkmk /]# mount -o nouuid /dev/centos11/root /mount
[root@checkmk /]# ls /mount
bin dev home lib64 mnt omd proc run srv tmp var
boot etc lib media mount opt root sbin sys usr
The snapshot is mounted successfully, and you can start to restore manually the data from the mounted volume
Remove the mounted snapshot volume once the data restoration is completed
[root@checkmk /]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 10G 0 disk
├─sda1 8:1 0 1G 0 part
└─sda2 8:2 0 9G 0 part
sdb 8:16 0 10G 0 disk
sdd 8:48 0 10G 0 disk
├─sdd1 8:49 0 1G 0 part
└─sdd2 8:50 0 9G 0 part
└─centos11-root 253:3 0 8G 0 lvm /mount
sr0 11:0 1 942M 0 rom
disksafe!sda 188:0 0 10G 0 disk
├─disksafe!sda1 188:1 0 1G 0 part /boot
└─disksafe!sda2 188:2 0 9G 0 part
├─centos-swap 253:0 0 1G 0 lvm [SWAP]
└─centos-root 253:1 0 8G 0 lvm /
[root@checkmk /]# umount /mount
[root@checkmk /]# dscli snapshot unmount sda timestamp=1584723025
Dismount snapshot with timestamp 1584723025 of sda
Command succeeded
Timeview in Management Console
Timeview (Snapshot Disk) is created from Timemark and assigned to CentOS host via ISCSI connection
