I'm curious about the behavior where any udev labeled device causes that corresponding listing to disappear from fdisk, sfdisk, or in the case of RDAC, lsvdev.
I have seen this on both EMC clariion and Sun Storagetek/Engenio 6540 arrays.
We use RHEL5.1 and udev to create persistent labels for Oracle devices.
Example udev rule:
# cat /etc/udev/rules.d/55-oracle-naming.rules
# Configure persistent, user-defined Oracle Clusterware device file names
KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id", RESULT=="3600a0b8000476694000004704974f509", NAME="ocr1", OWNER="root", GROUP="oinstall", MODE="0640"
KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id", RESULT=="3600a0b80004793a2000004ae4974e92d", NAME="ocr2", OWNER="root", GROUP="oinstall", MODE="0640"
KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id", RESULT=="3600a0b8000478034000003e04974f6f0", NAME="ocr3", OWNER="root", GROUP="oinstall", MODE="0640"
KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id", RESULT=="3600a0b80004793da000004904974e9b1", NAME="vot1", OWNER="oracle", GROUP="oinstall", MODE="0640"
KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id", RESULT=="3600a0b8000476694000004734974f778", NAME="vot2", OWNER="oracle", GROUP="oinstall", MODE="0640"
KERNEL=="sd*", BUS=="scsi", PROGRAM=="/sbin/scsi_id", RESULT=="3600a0b80004793a2000004b14974ea59", NAME="vot3", OWNER="oracle", GROUP="oinstall", MODE="0640"
I'm comfortable that we can always reference the /dev/ocr* or /dev/vot* devices, I'm just looking for how to explain this behavior. Is there some mechanism under the hood causing it? Is it so someone doesn't do things with those fdisk listed devices and inadvertently wipe out udev labeled ones?
Thx