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RN626X: Data array missing from mdstat after OS reinstall (password recovery)
Hi all, Hoping someone can help me safely recover my data array. Details below: MODEL: ReadyNAS RN626X, 6 disks, RAID 5, ~18TB data (OS 6) TIMELINE: 1. Admin password stopped working unexpectedly. 2. I pressed the physical reset button on the back of the unit (short press). This did not fix the password, but it did reset the network settings to DHCP (IP address changed). 3. To recover the admin password, I performed a proper OS reinstall via the boot menu (Reset + Power, held until boot menu appeared, selected "OS reinstall"). This successfully reset admin/password to defaults and I could log into the web interface again. 4. However, after logging in: - System > Volumes shows "data-0" as Healthy (green), RAID 5, Data 18.17TB, Free 0 — looks intact. - There's also a second entry called "data" (blue), 0TB, RAID unknown — assume this is a fresh empty placeholder from the reinstall. - System > Shares shows a warning: "No volume exists. Navigate to System -> Volumes page to create a volume." 5. I have NOT clicked "create a volume" or removed any disks, since I'm worried this could format/wipe the existing array. 6. Tried a normal system reboot (not another OS reinstall) — same result persists. DOWNLOADED LOGS — mdstat.log shows only two arrays: md0 : active raid1 (6 disks) — 4GB, this looks like the OS partition md1 : active raid10 (6 disks) — ~1.5GB, created Jul 10 2026, likely a system/swap partition There is NO third array shown for the actual ~18TB data volume. All 6 disks show as active/clean in both md0 and md1, so I don't believe there's a hardware/disk failure — it looks like the data array simply isn't currently assembled after the OS reinstall. QUESTION: Is it safe to manually reassemble the missing data array via mdadm/SSH, and if so, could someone walk me through the correct approach for OS 6 (BTRFS-based) so I don't make things worse? I have not attempted any commands yet — waiting for guidance before touching anything. Happy to post the full mdstat.log output, disk info, or other log files on request. Thanks in advance for any help!