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Forum Discussion
ReadyNAS 104 RAID5: 'Remove inactive volumes' after crash during resync - recovery needed
Hi all,
I have a ReadyNAS RN104, firmware 6.10.8, with 4x WD Red 3TB (WD30EFRX) in RAID5 (X-RAID). I'm hoping for guidance on safely reactivating my volume without losing data - I do NOT want to guess or experiment further, since I already know that's risky.
SETUP / TIMELINE
- Disk in bay 3 was reported FAILED (confirmed via admin panel, matching blinking LED, and SMART data showing high ATA error count / pending sectors, while bays 1, 2, 4 were clean or only minor).
- I bought an identical replacement WD30EFRX and did a partial backup (docs, photos, music) to an external USB drive before touching anything.
- After disconnecting the external drive, the system automatically started a resync on the degraded volume.
- ~18 minutes later, per the system log: another disk (Channel 2, log-based indexing) went from ONLINE to FAILED during the resync, the resync target disk (Channel 3) went from RESYNC back to ONLINE, and the volume health changed from Degraded to Dead. The system then warned it would auto-shutdown in 30 minutes.
- I shut the system down manually and physically replaced the old failed disk in bay 3 with the new one.
- On power-up, I got: "Remove inactive volumes to use the disk. Disk #1,2,4." and the Volumes page shows two entries: "data-0" (8.17TB data, RAID5, red status) and a second "data" volume (0 data, "RAID unknown", red status).
CURRENT STATE (from volume.log dump)
- RAID data-0: Level 5, State: inactive, Members: 4, but only 3 disks currently listed under it: sdd (bay1), sdc (bay2), sda (bay4) - all three show no Reallocated Sectors, no Uncorrectable Sectors; sdc has Current Pending Sector Count: 2, others 0.
- The "data" pool (the second, empty one) has a null UUID (000...000), Type: btrfs, 0 disks assigned - looks like a stale/ghost volume reference, not a real data container.
- Maintenance history log shows two earlier resilver operations (2026-07-11 and 2026-07-25) that both completed but left the pool "degraded", and a third resilver started 2026-07-27 that has no end_time/result - this is the one that was interrupted by the crash described above.
- New disk in bay 3: brand new, 0 power-on hours, not yet part of any pool (no Pool: line in its log entry) - as expected, it hasn't rejoined the array yet.
WHAT I'M ASKING
Based on what I've read about ReadyNAS event-count mismatches after an unclean shutdown/crash during resync, this looks like it could be a recoverable case (3 consistent disks, no reallocated/uncorrectable sectors) rather than a true double-disk failure - but I don't want to force-assemble anything myself without being sure of the exact commands/parameters for my array, since I've read that experimenting further can easily make things worse.
Netgear won't open an official support case since the RN104 is out of support. I do NOT have a complete backup (only partial, done just before the crash), so I'd really appreciate guidance from someone experienced with forcing a safe mdadm/BTRFS re-assembly on ReadyNAS OS6, or confirmation on what "Remove inactive volumes" actually does in this specific situation before I click anything.
I have the full log zip ready and I'm happy to share it privately (PM) with anyone willing to take a look - didn't want to post it publicly here. Thanks in advance for any help.
1 Reply
You were smart not to experiment. Have you tested the failed drives with vendor tools to see if they are accessible at all?
What happened to you is exactly why you need to make a full backup before replacing a drive and really should keep a backup current daily. You do not have three consistent drives because a second drive failed before the other failed drive's replacement completed re-sync. Especially if all the drives are the same age, that's the case all too often because a re-sync puts extra strain on the drives. If either of the failed drives work well enough to clone it, you may be able to recover at least some of the files. If not, your chances are poor. I'm sure StephenB will offer to look at your logs, but you can't upload zip files here. So put it in DropBox, Google Drive, etc. and prepare to share the URL in a PM when he asks for it.
data and data-0 are two parts of your RAID that the OS cannot put together, so do not attempt to delete or do anything to either. Doing so will reduce your chances of recovery even more.
The 7/11 and 7/25 re-syncs ending as "degraded" means you already had one bad drive at that time.
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