hi,
i have a host with a LSI SAS 3108 RAID controller in JBOD mode with 4 SSD SATA disks. i installed oVirt node (= CentOS 7) on the first two disks configured as SW RAID 1 (in the oVirt node/CentOS installer). when i look at the device names in the running OS i get
# lsscsi --scsi_id -g [0:0:0:0] disk ATA SAMSUNG MZ7LM480 204Q /dev/sda - /dev/sg0 [0:0:1:0] disk ATA SAMSUNG MZ7LM480 204Q /dev/sdb - /dev/sg1 [0:0:2:0] disk ATA SAMSUNG MZ7LM480 204Q /dev/sdc SAMSUNG_MZ7LM480HMHQ-00005_S2UJNX0J102216 /dev/sg2 [0:0:3:0] disk ATA SAMSUNG MZ7LM480 204Q /dev/sdd SAMSUNG_MZ7LM480HMHQ-00005_S2UJNX0J102214 /dev/sg3
# ls -l /dev/disk/by-id/*SAMSUNG* lrwxrwxrwx. 1 root root 9 9. Okt 12:07 /dev/disk/by-id/ata-SAMSUNG_MZ7LM480HMHQ-00005_S2UJNX0J102212 -> ../../sdb lrwxrwxrwx. 1 root root 10 9. Okt 12:07 /dev/disk/by-id/ata-SAMSUNG_MZ7LM480HMHQ-00005_S2UJNX0J102212-part1 -> ../../sdb1 lrwxrwxrwx. 1 root root 10 9. Okt 12:07 /dev/disk/by-id/ata-SAMSUNG_MZ7LM480HMHQ-00005_S2UJNX0J102212-part2 -> ../../sdb2 lrwxrwxrwx. 1 root root 9 9. Okt 12:07 /dev/disk/by-id/ata-SAMSUNG_MZ7LM480HMHQ-00005_S2UJNX0J102214 -> ../../sdd lrwxrwxrwx. 1 root root 9 9. Okt 12:07 /dev/disk/by-id/ata-SAMSUNG_MZ7LM480HMHQ-00005_S2UJNX0J102216 -> ../../sdc lrwxrwxrwx. 1 root root 9 9. Okt 12:07 /dev/disk/by-id/ata-SAMSUNG_MZ7LM480HMHQ-00005_S2UJNX0J102222 -> ../../sda lrwxrwxrwx. 1 root root 10 9. Okt 12:07 /dev/disk/by-id/ata-SAMSUNG_MZ7LM480HMHQ-00005_S2UJNX0J102222-part1 -> ../../sda1 lrwxrwxrwx. 1 root root 10 9. Okt 12:07 /dev/disk/by-id/ata-SAMSUNG_MZ7LM480HMHQ-00005_S2UJNX0J102222-part2 -> ../../sda2 lrwxrwxrwx. 1 root root 10 9. Okt 12:07 /dev/disk/by-id/dm-name-SAMSUNG_MZ7LM480HMHQ-00005_S2UJNX0J102214 -> ../../dm-6 lrwxrwxrwx. 1 root root 10 9. Okt 12:07 /dev/disk/by-id/dm-name-SAMSUNG_MZ7LM480HMHQ-00005_S2UJNX0J102216 -> ../../dm-5 lrwxrwxrwx. 1 root root 10 9. Okt 12:07 /dev/disk/by-id/dm-uuid-mpath-SAMSUNG_MZ7LM480HMHQ-00005_S2UJNX0J102214 -> ../../dm-6 lrwxrwxrwx. 1 root root 10 9. Okt 12:07 /dev/disk/by-id/dm-uuid-mpath-SAMSUNG_MZ7LM480HMHQ-00005_S2UJNX0J102216 -> ../../dm-5
disks 2:0 + 3:0 are configured as multipath devices (and subsequently set up by device mapper), disks 0:0 + 1:0 are not. SAMSUNG_MZ7LM480HMHQ-00005_S2UJNX0J102216 and SAMSUNG_MZ7LM480HMHQ-00005_S2UJNX0J102214 are listed in /etc/multipath/wwids (and get re-listed after reboot when i manually remove them).
why are two of the four local disks configured as multipath devices? As far as i understood documentation this shouldn't happen
thx 4 help matthias