Slow boot boot initialization on machines with Intel Optane DC Memory causing auto-mount to fail
This document (7023909) is provided subject to the disclaimer at the end of this document.
SUSE Linux Enterprise Server 12
/dev/pmem0 /mnt/pmem0 xfs dax,nofail 0 0/dev/pmem1 /mnt/pmem1 xfs dax,nofail 0 0
Namespaces need to be created individually. That means, you need to execute the following command for each namespace you want to create:
ndctl create-namespace --mode=fsdax --map=dev
- Both SLES12 SP4 and SLES15 emit a WARNING with stack trace, which is quite visible in dmesg.
--- cut here ---[ 577.289407] Device driver nd_pmem initialization / probe took 542228 ms to complete, report this[ 577.289418] ------------[ cut here ]------------[ 577.289428] WARNING: CPU: 4 PID: 1950 at ../kernel/module.c:3879 load_module+0x1a19/0x2190--- cut here ---This tells us that the module took 542s to initialize and that is considered long enough to trigger a generic warning in the modules loader. This conditional is not fatal in itself but userspace triggering a message the module load might have its own thresholds and failure modes.
- Both SLES12 SP4 and SLES15 will create a NMI warning message when changing and destroying a large "fsdax" or "devdax" namespace.
--- cut here ---NMI watchdog: BUG: soft lockup - CPU#<CPU-ID> stuck for 23s! [ndctl:<PID>]--- cut here ---
- SLES12 SP4 boot procedure stops at emergency shell without any change to /etc/fstab and the default systemd timeout value of 90 sec.
- SLES15 boot procedure stops at emergency shell if user modifies /etc/fstab to have entries to mount pmem devices (without nofail) while the default systemd timeout value remains 90 sec.
--- cut here ---
[Service]TimeoutSec=1200sExecStart=/usr/bin/udevadm settle -t 300--- cut here ---
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- Document ID:7023909
- Creation Date: 03-Jun-2019
- Modified Date:21-Apr-2021
- SUSE Linux Enterprise Server
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