Inner secrets of Synology Hybrid RAID (SHR) – Part 2b – My Synology case

At about 30% into the reshaping phase (after the first disk swap), my NAS went unresponsive (disconnected both shell and GUI), and I had to wait all day until I came home and did a hard reset on it and hoped everything went well..

In the meantime, I logged a case to the Synology support. They were not of any direct help, and the hard reset did take the NAS back to continuing the reshaping process.

My case with Synology support

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2020-12-01 13:51:37
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Replaced one of the smallest drives in my NAS yesterday (SHR) as a first step for later expansion (I will replace all drives with larger ones before expanding – if possible to delay any automatic expansion until then).

About 80% finished with rebuilding yesterday, but for some reason it started over after the first round.

Today about 30% finished when I lost the connection to the NAS (over ssh and the web interface). It does not auto-reboot and does not respond to ping.

To lessen the risk of data loss, what should my first step be ? Can I just pull the plug and hard-reboot the NAS with the current disks mounted (14TB, 3TB, 3TB, 8TB, 8TB in a SHR config), or is it better to replace or remove the disk that I recently replaced (in slot 1: 14TB in place of the previous still untouched 3TB) ?

What are the steps to getting the volume back online if it does not mount automatically ?

As the NAS is down, I am not able to upload any logs, but attached is the rebuild status before the crash.

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2020-12-01 15:28:58
Synology response (besides the auto response “send us logs”)
Not useful at all, exactly what I did, “Mark” who replied did not read anything..
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Hello,

Thank you for contacting Synology.

If you wish to replace a drive in your unit, please perform these steps one by one allowing for the repair to complete before replacing any further drives.
1. Pull out the drive in question.
2. Insert a replacement drive.
3. Proceed to the Storage Manager > Storage Pool > select the volume in question and click “Manage/Action”
4. Run through the wizard to repair the volume in question with the replacement drive.
5. Once complete, proceed to the Storage Manager > Volume and Configure/Edit the volume to configure the volume to have additional size.
Please see the link below for more help.
https://www.synology.com/en-uk/knowledgebase/DSM/help/DSM/StorageManager/storage_pool_expand_replace_disk

Please bare in mind that you benefit from the additional space from the drives you will need to replace at least 2 drives for larger ones in RAID 5/SHR or 3 drives in RAID6/SHR2.
You can see the type of RAID used via – DSM > Storage Manager > Storage Pool.

If you have any further questions please do not hesitate to get in touch.

Best Regards,
Mark

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2020-12-01 16:02:14
My reply
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Ok, so I restart the problem description then:

I did (yesterday):
0. Power down Synology
1. Pull out the drive in question.
2. Insert a replacement drive.
3. Proceed to the Storage Manager > Storage Pool > select the volume in question and click “Manage/Action”
4. Run through the wizard to repair the volume in question with the replacement drive.

THEN, today:
4b. Today about 30% finished when I lost the connection to the NAS (over ssh and the web interface). It does not auto-reboot and does not respond to ping.

SO what now ?
As the NAS is unresponsive I will never reach step 5:

To lessen the risk of data loss, what should my first step be ? Can I just pull the plug and hard-reboot the NAS with the current disks mounted (14TB, 3TB, 3TB, 8TB, 8TB in a SHR config), or is it better to replace or remove the disk that I recently replaced (in slot 1: 14TB in place of the previous still untouched 3TB) ?

What are the steps to getting the volume back online if it does not mount automatically ?

Also, is there an option to DELAY the expansion until all drives have been replaces, as you replied changeing the first drive will not expand the volume, but I’m not there yet since I’m stuck in a crash (unresponsive system)

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2020-12-02 23:25:46
My reply on Synologys’ suggestion to collect logs using the support centre
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How do I launch “Support Center” on the device when it is unresponsive (which was my initial question – what to do when it hangs in the middle of repairing/reshaping) ?

I forced it off and restarted and hoped for the best – reshaping continued and the second disk is now in reshaping mode.

My other question has not yet been answered:

Is it possible to delay the time consuming step of reshaping until all disks have been replaced ?

Initial configuration: 3TB 3TB 3TB 8TB 8TB

After replacement of the first disk: 14TB 3TB 3TB 8TB 8TB, after reshaping the first disk got a partition to match the 8TB disks.

After replacement of the second disk: 14TB 14TB 3TB 8TB 8TB, while reshaping again, now disk 1 and 2 looks similar with one partition matching the largest of the remaining 3TB disk, one matching the largest on the 8TB disks and the remainder (roughly about 6TB) the same on both 14TB disks.

When replacing the third 3TB disk, I assume the following would happen:
(14TB 14TB 14TB 8TB 8TB)

On the first and second disk, the (about) 3TB partition will be replaced with a partition to match the 8TB disks. Then the remainder (3 disks with 6TB unallocated space) will be used for another raid5 (after yet another reshape)

So my question again; is it possible to delay reshaping until I have had all the disks replaced. I understand that the “rebuild” is needed in between every replacement, but “reshape” should be needed only once.

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2020-12-03 12:19:07
Synology response
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Hello,

Thank you for the reply.

I’m afraid you cannot delay or prevent this process, once it starts it needs to run until fruition.

I would suggest to leave this running for now, if the volume does crash fully in the mean time I can take a look at what we can do to recover the volume, but there is not much I can do currently I’m afraid.

If you have any further question please do not hesitate to get in touch.

Best Regards,
Mark
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The crash

https://unix.stackexchange.com/questions/299981/recover-from-raid-5-to-raid-6-reshape-and-crash-mdadm-reports-0k-sec-rebuild
https://www.google.com/search?q=restart+synology+while+rebuilding
https://community.synology.com/enu/forum/17/post/20414

General SHR and mdraid links

https://www.youtube.com/results?search_query=synology+shr
https://bobcares.com/blog/raid-resync/
https://www.google.com/search?q=mdraid+reshape