meat

well the good news is.. on the second attempt I've gotten to the point where it's only the 18TBs left and the speed nearly doubled, writing at 165MB/sec now... fingers crossed it keeps this up.

that's interesting.. I'm not sure what that would have been, those 2 disks would have essentially be done with their part of the sync as I was way past the 4TB point.. Not sure if the actual diagnostic running wrote at that time or not... I've restarted the sync and it's humming along for now.. at 16.1% Tomorrow morning I should know if it's going to hang at the 50% spot again and I will look into those drives, etc.. for now I guess just wait it out..

Help me to understand what you are seeing in the diags to show that something else is hitting the array, or explain what else can hit the array, I'm drawing a blank on anything that could be.. VMs and Docker off and nothing on the network hitting it, I even killed network just to be safe.. I'm not sure what else internal to unraid would be hitting it.. system files and logs hitting the cache, watching the drive read / writes, I'm only seeing what would appear to be a parity sync. If something else accessing it, I'd see way more reads or writes. Are there processes in place that will throttle the sync for any reasons if say for example, CPU utilization gets too high? If that were the case, possibly it got stuck in that mode even after CPU dropped down. When it first started getting slow, everything just bogged down, I knew it had dropped off because my VM I had running had stopped working.. CPU was high at that time, that's when I shut everything down except the sync.. but those speeds never came back up.. I cleaned up cache and the cache returned to normal utilization levels, I was able to then turn back on VM and it all worked.. but the sync speeds never returned to what they should be.

Absolutely nothing else is accessing it, I had turned off Docker and VMs, even killed network for a while to test to make sure of that, and yes, as I mentioned in my post, there were 69 read errors early on in the process and it ran smooth for several hours after that.. My cache pool was pretty full, all my isos, appdata, system, logs, and domains are on the cache pool and I was able to free up a good amount of space by removing some snapshots, and that made things go slightly better, it allowed me to turn the VMs and Docker back on, which makes sense, but it didn't really do anything for the parity sync. I turned Docker and VMs back off to let it run a bit more but it would still top out at 2.0MB/sec max which appeared to be a write limitation. Finally I just cancelled it, rebooted, and started over.. Wait to see if it slows again around the 50% mark.

I'm in the process of rebuilding my parity. I had updated a few drives to 18TB so I could later move off a bunch of my 2TB drives and shrink the array. Rebuild was going great for the first 24 hours or so.. I had approx. 28 hours to go and then the speed dropped way off and the estimated time jumped up to 60+ days. I turned off the VMs and the Docker services so the only thing running would be the rebuild and that helped a bit, but it's still saying around 30 days. In the past 10 hours it has gone from about 54% complete to 55.6% complete. CPU utilization is only at 3% or so RAM at 16%. I did have some read errors on one of the disks earlier on in the rebuild.. 69 errors on one of the 18TB drives (disk20) but when that happened it really didn't slow anything down and ran strong for hours after that. At this point, all of the 2-4TB disks are no longer being read, just the 6 18TBs, so I actually thought it would run faster at this point. I'm really not sure what to do at this point as everything appears to be running fine, just extremely slow for whatever reason. unraid-diagnostics-20250316-1036.zip

well I went ahead and used the "New Config" option and I'm in the process of re-building the parity. I'll look into finding a new USB drive.. hopefully one that lasts.

Is there any reason why this would only be happening during a parity check or is there any other reason other than a power/connection issue that multiple disks drop offline? And thanks for the heads up on the USB.. I just replaced that USB maybe 6 months ago..

A month ago I had a similar issue where all of my disks were both active on the array but also showing up in the unassigned devices. I took some screen shots this time and I download the diagnostics.. this time the log seems to be more in tact than that last time. I rebooted and everything came back online with the exception of the Parity & Parity 2.. they show the RED X (disabled). Just like last time, this is happened at the beginning of the month towards the end of running the scheduled parity check, I don't know if is detecting errors and causing the issues or not. unraid-diagnostics-20250303-1320.zip

I think in this case that might not have been the case since everything was working up until right around the time the parity check completed, which took 4 days, but during the entire parity check you'll see that there were errors from the start. Maybe it's unrelated. I'll re-check and see what happens.

No power splitters are used, most disks are in a NetApp disk shelf and a few are in the drive bays of the server. Both the Server and the DS have dual power supplies. I'll run it again and see what happens. I'm not sure why all the logs weren't there, the syslog was empty and the syslog.1 only went to the 1st of the month so I'm missing any information on what actually happened. I'll go ahead and mark this as complete since everything at the moment is actually working, if I have issues again I'll open a new thread.

This morning I noticed all my shares were gone. The Array appeared normal but when I looked in the Unassigned Disk Devices, every disk showed up in there as well. My parity check showed complete with thousands of errors. I pulled a diagnostic, I'm not sure what that will show but it's attached. I then rebooted and started the array and everything was fine. The array didn't auto start like I though it normally did, but I may have disabled that, I'll have to double check. Everything seems normal now but I have no idea if my parity is actually valid or not. Hoping someone smarter than me can tell me what's going on here. unraid-diagnostics-20250204-0446.zip

Thank you for your help today. I'll let that run. Not sure how that happened, maybe my UPS is bad and we had a quick power failure.

just want to make sure I don't screw up this "new config" step. I had to do it once in the past a few years ago but I don't remember exactly what was involved. Right now the array is stopped. Disk 10 is unassigned. The disk with the data is an unassinged drive right now and all the data appears to be intact. Parity had a read error but Parity 2 is good. Do I re-assign the drive into Disk 10? Then chose Preserve ALL on the New Config and hit apply?

OK, so when mounting it as an unassigned disk it looks correct. So now just re-assign into disk 10 and do a new config?

well it mounted that time, when I look in it, it just has lost+found. Do I need to copy that over to another drive for safe keeping before I try to rebuild? Will rebuild restore it back to the way it was?