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Volume management
38 Dell EMC SC Series: Red Hat Enterprise Linux Best Practices | CML1031
5. Copy/export the data from the alternate system and import the data back to the parent system.
6. Validate the restored data.
3.12.3.3 Mount view volumes on the same system as the parent volumes to extract data
The view volumes contain exactly the same data as the parent volumes including any filesystem labels, disk
partitions, UUIDs, LVM metadata, and other application metadata (such as Oracle ASM labels). It is
recommended to mount the view volumes on an alternate system to avoid mixing up the parent volumes and
the view volumes. If the view volumes must be mounted along with the parent volumes on the same system,
additional steps must be taken to modify the metadata on the view volumes to avoid volume conflicts and
duplicates.
1. Create view volumes from the desired snapshots in the DSM GUI.
2. Capture information of parent volumes (includes device files, WWN, UUID, labels, multipath, and
LVM information) on the parent system before mapping view volumes to the same system.
- multipath –ll
- vgdisplay -v $VGNAME
- lsscsi –is
- blkid
- lsblk -aso name,min-io,opt-io,phy-sec,log-sec,sched,disc-max,serial
- scsi_id
3. Map the view volumes to the parent system.
4. Scan for the view volumes.
5. Identify the view volumes on the parent system and modify the metadata on the view volumes.
Note: /dev/mapper/mpathX represents the view volume multipath device file.
a. Change LVM volume group name and the UUIDs for the physical volumes and volume groups.
# vgimportclone --basevgname $NEW_VGNAME /dev/mapper/mpathX
b. Change the filesystem label if applicable
# tune2fs -L $NEW_LABEL /dev/mapper/mpathX (for ext4)
# xfs_admin -L $NEW_LABEL /dev/mapper/mpathX (for xfs)
c. Change the filesystem UUID.
# tune2fs –U random /dev/mapper/mpathX (for ext4)
# xfs_admin –U generate /dev/mapper/mpathX (for xfs)
6. Mount the filesystems on alternate mount points.
7. Copy/export the data from the view volumes and import the data back to the parent volumes.
8. Validate the restored data.
9. Remove and unmap the view volumes after the restore is successful and validated.
3.12.4 Recovering from a boot-from-SAN snapshot view volume
A snapshot view volume of a boot-from-SAN volume, when presented back to the same Linux system, is
automatically bootable as long as the boot partition and volume are referenced by their UUIDs and LVM
names inside of /etc/fstab, /boot/grub2/grub.cfg or /boot/grub/grub.conf. Additionally, the entries and