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Destroying EDA volume switched form XRAID and now I can't switch back.
I have a 516 with two external eSATA enclosures, an EDA500 and another brand 5-bay one the NAS identifies as an EDA500. Something happened while the EDA500 volume was in scrub. The NAS became unresponsive in both the GUI and SSH. But the EDA was clearly no longer being accessed -- the drive actvity LEDs were on solid. It wouldn't even respond to the front display or trying to power off with a double-press of the power button. My only solution was a long press of power and re-boot.
The NAS would not boot, stuck at some low percentage, and I tried multiple times. I then disconnected the EDA and it booted, showing my old "eda1" volume as dead. I re-connected the EDA with power on, and it now showed "eda1-0" and "eda1-1" and the feared "remove inactive volumes" message. It was trying to mount a second volume as "eda1", which it can't do. But it did show all the drives were healthy. I've seen this happen when a single drive is out of sync, so I tried every combination of 4 of the 5 drives to see if that would work. No luck.
So, I resigned myself that I'd need to destroy the old eda1 volume, then see if it would re-import the one on the EDA. If it didn't import, I would need to zero the drives, re-create the volume, and restore from backup because the volume was corrupt. That would also be a good process to insure there really is nothing wrong with the drives. When I went to do the DESTROY, I did note that it said it would disable XRAID. No problem, I thought, I can just change back later.
I did the DESTROY with the EDA disconnected, so nothing was done to the actual volume, but the NAS "forgot" about it. But then, the EDA volume wouldn't import. But that's a problem for another day. It's data I don't access often, and I still have my backup even if the volume is corrupt.
But now I can't switch back to XRAID. The NAS claims I cannot because I have "expanded volumes". Yes, I do; and XRAID expanded them. Both the main NAS volume and the other eSATA chassis have volumes consisting of two RAID groups because the drive sizes were upgraded. Thinking back, maybe having two RAID groups was part of the problem re-attaching the EDA. I know I had to do that once before and it worked. Maybe that was before expansion, I don't recall. Or maybe it is just that the volume really is corrupt.
Is there any way short of reformatting either the other eSATA volume or even the whole system for me to get back to XRAID before I re-attach the EDA500? I wasn't looking forward to restoring just the EDA500. I'm looking forward even less to the potential of restoring 32TB of data to the whole system. But I want the expandability of XRAID back.
I'm afraid to do anything with the EDA500 while the NAS is in FlexRAID mode since it may not be compatible with going back to XRAID, even though it will no longer be an expanded volume. All drives are like sizes, so only one RAID group will be created. But I don't want to have to do anything with it twice, once in FlexRAID mode and then again in XRAID (if I ever get there).
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You aren't supposed to be able to use XRAID with the expansion units, so the real puzzle here is how you were able to use XRAID before.
There's a lot of risk in having a single volume span two or three chassis, so you really shouldn't do that.
I don't have volumes spanning chasses (I agree, bad idea -- I would have lost more with this event if I did). And so long as I didn't do that (which it actually wouldn't let me do in XRAID mode, anyway) or have multiple volumes in a single chassis, the NAS was perfectly happy with XRAID being enabled and actually expanding the volumes. This appeared to be normal behavior. My 4200V2, on the other hand, would not allow two volumes in the single chassis with XRAID when I ran some experiments before putting it in service as my backup device. Note that trying to switch to XRAID is not complaining that I have multiple volumes, as it did with two volumes in the 4200V2, it's complaining the volumes are expanded. And I know I did once have to disable XRAID in order to get the "lost" volume of the EDA restored into the active arrays, and I was able to swap it back later. But apparently, that was before the expansions. It was actually a situation very much like where I am now, except I think the EDA volume was intact then and isn't now.
I started with 4x6TB + 2 * 4TB in the 516 and 4*3TB in the EDA, so I started with two RAID groups. I moved the 4TB's to the EDA (filling the last slot and swapping out one 3TB), replacing them with 6TB's in the 516, thus creating a second layer in the EDA as well. And then I later replaced the remaining EDA 3TB's with 4TB's. Each time, XRAID did the expected "magic" and expanded the array. This was all a while back, probably on OS around 6.7.something. I later put the 3TB's into the other brand eSATA chassis and created yet another volume in XRAID on it. That was definately in OS 6.8.something or better.
Now, maybe with the EDA500 being twlighted, that support is no longer there in 6.9+., or at least tested (and unknowingly broken). Or, as you say, maybe it was an unitentional feature that unfortunately went away But, wow, it sure worked well for somehting unplanned. It would be a shame if the capability is lost, but it sure would be nice to know if it's worth me trying to get the unit back into XRAID or if it's a fool's errand.
I'm trying an experiment using a 312 I bought used for who-knows-why (and now, I guess I know why). I put it in FlexRaid mode, hooked to it the EDA containing three spare drives, and I'm currently syncing a RAID5 volume. The existing 312 volume is not expanded. When it's done, I'm going to see if I can switch to XRAID or not.. It's all data I don't care about, so a perfect test set-up. I also plan to export and -re-import it to see if I can plan to rebuild the array and restore the data using the 312 and move it to the 516. Unfortunately, I need the EDA "back", so I don't have an infinite time to play with it. But if there is anything else you'd like to see tried with this combo, let me know soon and I'll try to work it in.
So, here is progress thus far:
I created a new volume on the EDA500 while in FlexRAID mode and then successfully changed to XRAID. I put a few files on it and then exported that volume and booted with the EDA disconnected, and the unit had "forgotten" the volume. I then re-connected the EDA with power off and booted, and the volume was imported, with the unit remaining in XRAID mode. As is typical with an import, I had to go in and set share access again, as it had been cleared by the export/import.
When I did that, md0 (the OS partition) began resync as a RAID 1 as well. The log didn't show the import or start of resync, just the export and later completion of resync. But TOP showed it was syncing md0 and the drive access LEDs were blinking like crazy. That only took a few minutes, and then all activity stopped on the EDA, all LEDs were solid, and everything worked just fine. So, it appears it was the expanded volume causing the problem switching to XRAID, just as the unit reported. But I'm not sure if it was the expanded volume or a corrupt volume that was preventing import of the original EDA volume.
I'm next going to re-create the original volume and restore the files to it using the 312. The reported CPU use during the creation of my test volume never topped 20%, so it's the eSATA speed that's the bottleneck and I don't expect things to go slower on the 312 compared to the 516 since the 312 will be doing nothing else.
What remains to be seen is if, after exporting the other eSATA volume, I can switch the 516 back to XRAID with just the one (expanded, two RAID group) volume so I can then import both eSATA volumes while in XRAID mode or if I'll have to destroy and re-create the data volume with the eda volumes exported to get back to XRAID. I'm not going to try that till the EDA volume is re-created and files are restored to it, so I don't have two file restorations in progress simutaneously if destroying the data volume becomes necessary.
It's going to take a few days before I'm ready for the next step. Resyncing a 5x4TB volume on an EDA500 and then restoring some 8TB of data will be time consuming.
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