RAID arrays start in degraded state at boot time

This document (7022307) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Server 11 Service Pack 4 (SLES 11 SP4)
SUSE Linux Enterprise Server 11 Service Pack 3 (SLES 11 SP3)
SUSE Linux Enterprise Server 11 Service Pack 2 (SLES 11 SP2)
SUSE Linux Enterprise Server 11 Service Pack 1 (SLES 11 SP1)

Situation

In an environment with many raid arrays it may be possible that not all arrays are assembled fully at boot time and come up degraded.
Assembling these RAID devices after boot works flawlessly.

Resolution

Insert a "sleep XX" statement right after the "start)" section in /etc/rc.d/boot.multipath.

Cause

It may be possible that devices during boot time, e.g. storage devices in large environments, appear more slowly than they are processed by udev. "udev settle" considers itself terminated once every pending event has been handled (meaning the queue of pending events is empty). If events come in very slowly it can happen that raid arrays are activated, even if they are still degraded.

From SLES12 onwards this is not possible anymore because RAID arrays are assembled incrementally and the system waits a long time for all devices to appear. Nevertheless, degraded arrays will be started after that time by the "mdadm-last-resort@.service".

Additional Information

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.

Document ID:7022307
Creation Date: 10-Nov-2017
Modified Date:03-Mar-2020
- SUSE Linux Enterprise Server
- SUSE Linux Enterprise Server for SAP Applications

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