Some time ago I configured a mirrored volume group of two physical volumes. When I configured this I had to define another volume for the mirror log. When I did this I was already wondering what would happen to my RAID1 configuration if the drive with the mirror log fails, but I was sure that there must be a way to define another mlog or get the data from the two mirrored volumes. The original mlog was located on a partition on the system drive.
Now I had to transfer the two mirrored physical volumes/hard drives to another machine and I am unable to mount the volume group without the corresponding mlog partition. If I take the system disc (containing the mlog partition) out of the old server and put it together with the two mirrored disks in the same machine, I can mount the volume. However, it is no option to transfer the system disk of the old server to the new machine. And how can I get my data back if the mlog is lost?
Isn't there a way to create mirrored volumes without an extra partition for the mlog? mdadm also doesn't require an extra partition for a mirror log.
How should I set up such a mirror log in a better way? If it is so essential, it should be redundant as well....
Thanks a lot!
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[root@device user]# lvs -a -o +devices WARNING: Device for PV TgCMKE-dwMs-l40L-BTPm-eboW-Rbza-FoDTce not found or rejected by a filter. LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert Devices ... lv_raid vg_mirror mwi---m-p- <931.51g [lv_raid_mlog] lv_raid_mimage_0(0),lv_raid_mimage_1(0) [lv_raid_mimage_0] vg_mirror Iwi---m--- <931.51g /dev/sdb1(0) [lv_raid_mimage_1] vg_mirror Iwi---m--- <931.51g /dev/sdd1(0) [lv_raid_mlog] vg_mirror lwi---m-p- 4.00m [unknown](0) ...