Updated udev packages that fix several bugs are now available for Red Hat Enterprise Linux 5.
The udev packages implement a dynamic device directory, exposing the devices currently present on the system. The directory runs in user space, dynamically creates and removes devices, ensures consistent naming, and provides a user-space API.
On system boot, the udev helper application, pam_console_apply, was called for every disk on the system. This was unnecessary for example for SCSI disks, which do not have default pam console permissions. As a consequence, the boot process was significantly slowed down if the system contained a large number of disks. To fix this problem, the /etc/udev/rules.d/95-pam-console.rules file has been marked as a configuration file and it will not be automatically updated with newer udev versions. System administrators should now comment out the pam_console_apply call in this file on systems that do not need non-root user access to devices.
Previously, the udev helper tool for loading firmware into drivers was logging to syslog only. Consequently, there was no output in the early boot stage when the syslog daemon was not running. With this update, if the udevd daemon is running in debug mode, the firmware_helper also logs to the console, which helps to debug firmware loading problems.
The WAIT_FOR_SYSFS variable in the udev rules was set to wait 3 seconds for a file in the sysfs file system to appear. This timeout was too low for some hot-added SCSI disks that need at least 6 seconds to spin up. Therefore no symbolic links in the /dev/disk/ directory were created. The WAIT_FOR_SYSFS variable has been set to 10 seconds, which is enough for most disks. This results in proper udev database entries and symbolic links.
Prior to this update, udev used the target's port identifier instead of the initiator's PHY identifier in the /dev/disk/by-path symbolic link. Consequent to this, when the disk was hot-removed and hot-added, the symbolic link used a different pathname. This bug has been fixed and udev now uses the correct initiator's PHY identifier in the symbolic link, which remains the same for re-added disks.
All users of udev are advised to upgrade to these updated packages, which fix these bugs.