# Drive 1 of 4 failed in the middle of D4 Repair **URL:** \ **Category:** Synology\ **Tags:** help, hyper-backup, hard-drive, hardware, volume\ **Created:** [August 26, 2023, 4:48pm UTC](https://forums.spacerex.co/t/drive-1-of-4-failed-in-the-middle-of-d4-repair/1145 "2023-08-26T16:48:07Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Boyd\_Wold](https://forums.spacerex.co/user_avatar/forums.spacerex.co/boyd_wold/32/614_2.png) [@Boyd\_Wold](https://forums.spacerex.co/u/Boyd_Wold)\ **Post date:** [August 26, 2023, 4:48pm UTC](https://forums.spacerex.co/t/drive-1-of-4-failed-in-the-middle-of-d4-repair/1145/1 "2023-08-26T16:48:07Z")
Setup: version: DS920+ RAID: SHR Drives: started with (4) 4TB ironwolf drives using 1 volume Current: (4) 14TB ironwolf drives inserted. - D1 - Critical - D2 - Healthy - D3 - Healthy - D4 - Repairing (39% done. Currently incrementing at about .08% per 24 hour period) (2) 1TB NVME drives configured as a second Volume. Both Healthy DSM 7.2 —– A week ago it had (4) ironwolf 4TB drives. I bought 4 new ironwolf 14TB drives No Backup I replaced Drive 1 - 3 and the volume repaired just fine each time. During Drive 4 replacement, Drive 1 went CRITICAL with UNC errors. The system slowed to barely useable. Simple actions like logging into the web interface took 5-10 minutes and many times failed. SSH also took 5-10 minutes to login and then another 5 minutes when I did a sudo -i - D1 utilization at 100% All other drives in volume are typically 0% but occasionaly show some usage. I have done a number of things to try and work through this. - Backing up during its current state is possible but so slow that I think it may take months at its current rate. - I removed the UNC errors in the database and restarted the machine to try and force a Healthy status in case it was a false error. Within 10 minutes of the system coming online, new UNC errors showed up so the the drive is going bad. I don’t know what to do at this point. I want to backup in the fastest way possible but I can’t seem to speed that process up because D4 isn’t able to be used yet in the volume. Anyone have ideas on how to proceed? ---
**Author:** ![Paul](https://forums.spacerex.co/user_avatar/forums.spacerex.co/paul/32/93_2.png) [@Paul](https://forums.spacerex.co/u/Paul)\ **Post date:** [August 26, 2023, 7:56pm UTC](https://forums.spacerex.co/t/drive-1-of-4-failed-in-the-middle-of-d4-repair/1145/2 "2023-08-26T19:56:15Z")
Difficult. What you did not mention (and it is the most relevant piece of information in the entire story) is the RAID type of your storage pool. I assume it is SHR or RAID 5 with 1-drive fault tolerance. The fact that you do not have a backup is something you probably regret much. But if I may ask, what were your considerations not to have one made regularly? I try to understand the logic people have. ---
**Author:** ![Boyd\_Wold](https://forums.spacerex.co/user_avatar/forums.spacerex.co/boyd_wold/32/614_2.png) [@Boyd\_Wold](https://forums.spacerex.co/u/Boyd_Wold)\ **Post date:** [August 26, 2023, 8:35pm UTC](https://forums.spacerex.co/t/drive-1-of-4-failed-in-the-middle-of-d4-repair/1145/3 "2023-08-26T20:35:58Z")
Hi Paul, You are correct, it is SHR. I’ll edit my original to include that important bit of info. Looking back, I can see what happened. The NAS was something I wanted for my home for sometime. I wanted to move my HTPC (Plex) and the surrounding services into a NAS run by docker. I picked up the synology because of the price. Got lucky on ebay and got it for $400 including the four 4TB drives. I then began the evolving journey of building a sweet home set up and I think I forgot along the way how hard it would be to rebuild if I lost everything. Nothing magic, just evolved into a more complex system over time. At the beginning, I was playing and felt like I would rebuild if I screwed something up. Now however, having this issue show up, I am making a list of what it will take to rebuild and I wish sincerely that I had a full backup. Side note, I just setup an S3 Glacier bucket for this purpose about 2 weeks ago and I was pushing small amounts of stuff up to it to test and see what the costs looked like. Again, kinda wish I had pushed the whole thing now. ---
**Author:** ![Paul](https://forums.spacerex.co/user_avatar/forums.spacerex.co/paul/32/93_2.png) [@Paul](https://forums.spacerex.co/u/Paul)\ **Post date:** [August 27, 2023, 9:08am UTC](https://forums.spacerex.co/t/drive-1-of-4-failed-in-the-middle-of-d4-repair/1145/4 "2023-08-27T09:08:49Z")
Hi Boyd, Thanks for sharing. Makes sense. Rebuilding a RAID with a new HDD often goes well, but not always. All the disks are pushed to their limits. With clients, I always make a backup first or demand it be made before proceeding with a drive swap.