you can telnet directly to the slot to get that information. Uptime for a stack will not change unless the stack completely goes down. Example output below:
System UpTime: 10 days 15 hours 8 minutes 40 seconds Slot: Slot-1 * Slot-2 ------------------------ ------------------------ Current State: MASTER BACKUP (In Sync)
Output after getting the output directly from Slot-2:
#relevant output is boot time:
Slot-1 EXOSTACK.2 # telnet slot 2 Entering character mode Escape character is '^]'. telnet session telnet0 on /dev/ptyb0 ExtremeXOS Copyright (C) 1996-2020 Extreme Networks. All rights reserved. This product is protected by one or more US patents listed at https://www.extremenetworks.com/company/legal/patents/ along with their foreign counterparts. ============================================================================== You are connected to a Backup node. Only a limited command set is supported. You may use "telnet slot <slot_number>" to connect to the Master node to access the full set of commands. Press the <tab> or '?' key at any time for completions. Remember to save your configuration changes. There have been 42 successful logins since last reboot and 0 failed logins since last successful login Last Successful Login was on: Tue Oct 11 08:01:27 2022 Slot-2 EXOSTACK.1 > show sw SysName: EXOSTACK SysLocation: PHL SysContact: GTAC System MAC: 02:04:96:B9:6E:DA System Type: X465-48W (Stack) SysHealth check: Enabled (Normal) Recovery Mode: All System Watchdog: Enabled Current Time: Tue Oct 11 08:03:04 2022 Timezone: [Auto DST Enabled] GMT Offset: -300 minutes, name is not set. DST of 60 minutes is currently in effect, name is not set. DST begins every second Sunday March at 2:00 DST ends every first Sunday November at 2:00 Boot Time: Tue Oct 11 08:00:05 2022 Boot Count: 210 Next Reboot: None scheduled System UpTime: 10 days 15 hours 9 minutes 11 seconds
"show system" always shows the "System Uptime" of the hole stack, but the "Boot Time" (shown three lines above the uptime) is the individual boot time of the respective slot your are logged in to. The uptime of the node you have to calculate by yourself, I think.