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RN314 re-syncing even though sync completed
RN314 from 2014... came with 4x1TB Toshiba MG03ACA100 drives. Noisy as hell, and out of space. So, in process of upgrading to Seagate ST4000DM004 4TB drives. This is for personal use, so not "mission critical" in terms of up-time:
- First swap: powered down (yes I know hot-swap is supported, not a fan of that concept as an EE), pulled Disk 4, inserted Seagate disk. System powered up, "Degraded Data" message, then proceeded to resync while complaining that disk speed didn't match the Toshibas. (This Seagate is a 5900RPM slogger.) Took 5 hours to 100% complete, with no errors, no issues. All good.
- Second swap: powered down, replaced Drive 3. Same process, except didn't complain this time about RPM mismatch. Took about 5 hours again, no errors, no issues.
- Issue: Left machine alone for an hour, came back to Swap out Disk 2. Checked the web interface once more first, and observed another "resyncing" was now in process, needing 9+ hours for completion. Closed/re-opened browser, re-logged in to double check, and yes, there is another "resyncing" process happening. Why?? The logs show the exact same messages as the first swap, as shown below. By 12:28pm, Disk 3 was back ONLINE, and the system shows all 4 drives are Green. And yet, this mysterious extra resyncing is taking place. The NAS is working fine. I can read all the files, all the system features are working as expected.
Is it safe to swap out the 3rd drive now? Or do I have to wait for this extra resyncing to finish? Why would it show all the drives as Green if it is still in the process of resyncing???
| May 11, 2020 12:28:11 PM | Disk: Disk in channel 3 (Internal) changed state from RESYNC to ONLINE. | |
| May 11, 2020 12:28:09 PM | Volume: Volume data health changed from Degraded to Redundant. | |
| May 11, 2020 07:54:14 AM | System: Antivirus scanner definition file was updated to 59.25809. | |
| May 11, 2020 07:20:35 AM | System: ReadyNASOS background service started. | |
| May 11, 2020 07:20:34 AM | Volume: Resyncing started for Volume data. | |
| May 11, 2020 07:20:14 AM | Volume: Volume data is Degraded. |
20 Replies
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That usually happens if there was an unexepected reboot or shutdown on the NAS. Have you notice if power went out?Also, have you checked the full logs under diskinfo.log or smarthistory.log for any possible drive issues?
I think it would be best to get your data backed up just in case.
Though Marc_V is correct in saying that sometimes spontaneous resyncs happen (and they need to be investigated when they do) - that isn't what is happening to you. This is a normal part of the vertical expansion process. As it happens, I am vertically expanding my own NAS at the moment, so this is top-of-mind.
jimk1963 wrote:
Is it safe to swap out the 3rd drive now? Or do I have to wait for this extra resyncing to finish? Why would it show all the drives as Green if it is still in the process of resyncing???
You need to wait for the second ("extra") resync to complete.
You have two different RAID groups on your system as a result of vertical expansion. When you inserted the second disk, the original 4x1TB RAID group first needed to be rebuilt. After that a new RAID-1 group of 2x3TB is created, and concatenated to the original group in your volume. The NAS for some reason reports both resync operations separately, and that can give you an incorrect impression that the process is complete.
You will see this again when you install the next two drives (which will take longer to complete than the first one, since there are more data blocks to process). The first RAID group gets rebuilt, the new one will be re-shaped (horizontally expanded).
If you have ssh enabled on the NAS, you can watch the progress with
watch cat /proc/mdstat
You'll see both RAID groups for the data volume (md126 and md127), and the status of the one being resynced. There are two much smaller RAID groups (md0 and md1) - md0 is the OS partition; md1 is the swap partition.
Stephen! Thanks again, incredibly helpful. I did let the second resync complete, which took over 10 hours. At midnight, dropped in the third disk, completed in about 5 hours again and Is now on a 20+ hour second sync, exactly as you described. Altogether this process is going to take around 3 full days, which really surprises me. Seems horribly inefficient. I'm wondering now if it would have been better to just copy everything to my larger NAS, replace all 4 drives at once, then just copy everything back. Only talking about 3TB. Seems that would have been way faster than this RAID rebuilding process.
As you continue through the process, you are much better off doing the hot swap, as that lets you and the NAS know what is going on as it happens (removal, insertion, and re-sync are logged). As an EE, you should know that the power pins on the drives are not all the same length, expressly to safely support hot swapping. Hot swapping with a cable where it may not go straight on can still be an issue. But in a NAS, they go in straight.
BTW, "DM" drives are a poor choice for a NAS (or any RAID). They wll likley suffer from premature failure and may cause other issues along the way. There is a reason NAS purposed drives were created.
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