I'm having a strange problem since I moved from Centos5 to Centos6. I have three disks, first two are used as a RAID1, and third one is a stand-alone backup disk that is not listed in /etc/fstab (it is mounded when needed and then unmounted).

My problem: After a boot, /dev/sdc exists but /dev/sdc1 does not. Also, the links in /dev/disks are also absent for the first partition of sdc. Disk itself is fine, and if I hot-remove it and plug it back in, /dev/sdc1 appears ok and everything is working.

My question: What subsystem manages auto-discovery of disks, partitions, etc. during the boot process (e.g. what creates /dev/disks/by-label)? How do I configure it to scan /dev/sdc too and create all relevant files and links in /dev ?

Edit: Here's the relevant part of dmesg output (the only place sdc appears). It does list sdc1, but it's not in /dev!

sd 1:0:0:0: [sdb] 1953525168 512-byte logical blocks: (1.00 TB/931 GiB)
sd 3:0:0:0: [sdc] 976773168 512-byte logical blocks: (500 GB/465 GiB)
sd 1:0:0:0: [sdb] Write Protect is off
sd 1:0:0:0: [sdb] Mode Sense: 00 3a 00 00
sd 1:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
sd 3:0:0:0: [sdc] Write Protect is off
sd 3:0:0:0: [sdc] Mode Sense: 00 3a 00 00
sd 3:0:0:0: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
 sdb:
 sdc:
sd 0:0:0:0: [sda] 1953525168 512-byte logical blocks: (1.00 TB/931 GiB)
sd 0:0:0:0: [sda] Write Protect is off
sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
 sda:
DMAR:[DMA Read] Request device [00:1e.0] fault addr 361bc000 
DMAR:[fault reason 06] PTE Read access is not set
 sdb1 sdb2 sdb3
 sdc1
 sda1
sd 1:0:0:0: [sdb] Attached SCSI disk
sd 3:0:0:0: [sdc] Attached SCSI disk
 sda2 sda3
sd 0:0:0:0: [sda] Attached SCSI disk