Large amount of GPT disks may cause slow-down in the boot process

This document (7023057) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Server 12

SUSE Linux Enterprise Server 12 Service Pack 1 (SLES 12 SP1)

SUSE Linux Enterprise Server 12 Service Pack 2 (SLES 12 SP2)

SUSE Linux Enterprise Server 12 Service Pack 3 (SLES 12 SP3)

Situation

This concerns only systems with a high number (i.e >100) of partitions on GPT ((G)lobally Unique Identifier (P)artition (T)able) partition tables running SUSE Linux Enterprise Server 12. Systems installed from a later version of SUSE Linux Enterprise Server (i.e. 15 and higher) are not affected by this issue.

For the affected case, there are many contenders for the symlink "/dev/disk/by-partlabel/primary" that may result in a noticeable slow-down in the (re)start of the systemd-udevd daemon, which in its turn can have a negative impact on either the boot process or on upgrade of the systemd package.

In order to prevent such a slow-down from happening, SUSE released a temporary workaround that prevents the creation of the symlinks "/dev/disk/by-partlabel/primary". The workaround is provided in package udev-228.<?insert_versions?>.

The true solution however consists in preventing YaST from creating duplicate partition names and resetting the partition names from "primary" or "logical" to an empty string. See the "Resolution" section below for details.

To verify if a system is affected run the following commands:

udevadm info -e | grep -c 'ID_PART_ENTRY_NAME=primary'
udevadm info -e | grep -c 'ID_PART_ENTRY_NAME=logical'

If one of the reported numbers is greater than 100, it should be considered to fix the system as the workaround will be removed again in future SLES releases (16 and higher). By the time the workaround is removed, there should not be hundreds of "primary" partitions on a system any more.

Resolution

If any systems already contain paritions with "primary" and "logical" partition labels, the "sgdisk" utility can be used ot reset the label to an empty string:

sgdisk -c $part_number:"" /dev/<device>

Where <device> is the disk device e.g. "sda" and $part_number indicates the partition number for which the label should be reset. Care should be taken to only do this on partitions that have the "primary" or "logical" label assigned.

To prevent creation of partitions with the default labels "primary" and "logical" in the future it is needed to install the update packages parted-<?insert_versions?> and yast2-storage-<?insert_versions?> or later. New installations of SLE12 (up to SP3) can be done as usual, resetting partition lables after installation as described above. Alternatively a DUD (Driver Update Disk) with the updated packages can be obtained by contacting SUSE Technical Support, which will prevent creation of the duplicate partition tables during installation.

Cause

SUSE Linux Enterprise Server 12 YaST creates all new Linux GPT partitions with the name "primary".

Disclaimer

This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.