[Nokia-7215][syslog] Syslog missing after reboot in 202205

[yaqiangz]

Description

Since 20220531.35 image, rebooting in Nokia-7215 would cause syslog before reboot miss.

Steps to reproduce the issue:

1. check syslog
2. reboot
3. check syslog

Describe the results you received:

1. Before log:

admin@hostname:~$ date
Tue 29 Aug 2023 08:00:16 AM UTC
admin@hostname:~$ sudo head -n 5 /var/log/syslog
Aug 29 08:00:06.146375 hostname INFO rsyslogd: [origin software="rsyslogd" swVersion="8.2102.0" x-pid="2378" x-info="https://www.rsyslog.com"] rsyslogd was HUPed
Aug 29 08:00:08.376712 hostname INFO logrotate[7317]: logrotate_script: 10: [: -gt: unexpected operator
Aug 29 08:00:08.382948 hostname INFO logrotate: Sending SIGHUP to OA log_file_name: /var/log/swss/sairedis.rec
Aug 29 08:00:08.456302 hostname INFO systemd[1]: logrotate.service: Succeeded.
Aug 29 08:00:08.456675 hostname INFO systemd[1]: Finished Rotate log files.

2. After log, syslog before rebooting is gone:

admin@hostname:~$ sudo reboot
requested COLD shutdown
/host: 10.6 GiB (11340886016 bytes) trimmed on /dev/sda2
Tue 29 Aug 2023 08:00:53 AM UTC Issuing OS-level reboot ...
admin@hostname:~$ date
Tue 29 Aug 2023 08:03:34 AM UTC
admin@hostname:~$ sudo head -n 5 /var/log/syslog
Aug 29 08:02:04.399252 hostname INFO kernel: [    0.000000] Booting Linux on physical CPU 0x0
Aug 29 08:02:04.399473 hostname NOTICE kernel: [    0.000000] Linux version 5.10.0-18-2-armmp ([email protected]) (gcc-10 (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2) #1 SMP Debian 5.10.140-1 (2022-09-02)
Aug 29 08:02:04.399485 hostname INFO kernel: [    0.000000] CPU: ARMv7 Processor [414fc091] revision 1 (ARMv7), cr=10c5387d
Aug 29 08:02:04.399490 hostname INFO kernel: [    0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
Aug 29 08:02:04.399503 hostname INFO kernel: [    0.000000] OF: fdt: Machine model: Nokia-IPD6448M-A38X-CUST1

Describe the results you expected:

Syslog doesn't disappear after rebooting.

Output of show version:

(paste your output here)

Output of show techsupport:

(paste your output here or download and attach the file here )

Additional information you deem important (e.g. issue happens only occasionally):

[vmittal-msft]

@prgeor we may need to provide option to choose from - dram or disk.
refer PR - #15077