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Forum Discussion
Possible Failed RAID5 to RAID6 Converstion
Hi I have a RN528X. I moved a 6 drive RAID5 (XRAID2) array from a RN516. This consisted of 4x14TB and 2x10TB. They have been vertically expanded before (6x6TB -> 6x10TB -> replace 4 with 14TB). ...
powellandy1 wrote:
So what exactly does the XRAID/FlexRAID toggle button in the GUI actually change??
In XRAID mode, the system automatically expands when new disks are added (or when smaller disks are replaced with larger ones).
If FlexRAID mode, you need to do all steps manually - creating RAID groups, or adding new disks to the appropriate RAID groups, and concatenating the RAID groups together.
powellandy1 wrote:
If I was able to convert md127 and all the prequisites of XRAID still existed (which I assume is to do with consistant arrays/partitions etc.. such that it can automatically expand) can it not be toggled back??
That should be possible. There are some scenarios when the system won't let you switch from FlexRAID to XRAID - I don't think they are all well characterized.
StephenB wrote:
powellandy1 wrote:
So what exactly does the XRAID/FlexRAID toggle button in the GUI actually change??
In XRAID mode, the system automatically expands when new disks are added (or when smaller disks are replaced with larger ones).
If FlexRAID mode, you need to do all steps manually - creating RAID groups, or adding new disks to the appropriate RAID groups, and concatenating the RAID groups together.
I understand that - is XRAID literally a boolean flag?? Is it automatically determined (by a set of rules) when the RAID system is in a state that it can automatically expanded??
Sandshark - I found this post of yours - https://community.netgear.com/t5/Using-your-ReadyNAS-in-Business/Reducing-RAID-size-removing-drives-WITHOUT-DATA-LOSS-is-possible/td-p/1736125
It seems to be what I want - although my circumstance is more complicated (multiple arrays).
root@MediaMaster:~# btrfs filesystem show /data
Label: '0ed5d010:data' uuid: f1374f27-204a-4692-96d6-554d85e68f77
Total devices 3 FS bytes used 44.47TiB
devid 1 size 27.27TiB used 25.81TiB path /dev/md127
devid 2 size 18.19TiB used 16.73TiB path /dev/md126
devid 3 size 14.55TiB used 2.08TiB path /dev/md125
root@MediaMaster:~# mdadm --detail /dev/md125
/dev/md125:
Version : 1.2
Creation Time : Thu Jun 4 05:01:37 2020
Raid Level : raid5
Array Size : 15623254016 (14899.50 GiB 15998.21 GB)
Used Dev Size : 3905813504 (3724.87 GiB 3999.55 GB)
Raid Devices : 5
Total Devices : 5
Persistence : Superblock is persistent
Update Time : Mon Aug 31 06:52:38 2020
State : clean
Active Devices : 5
Working Devices : 5
Failed Devices : 0
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 64K
Consistency Policy : unknown
Name : 0a436c4c:data-2 (local to host 0a436c4c)
UUID : 9b299c45:6236c52f:26afdb09:a5615851
Events : 18795
Number Major Minor RaidDevice State
0 8 37 0 active sync /dev/sdc5
1 8 53 1 active sync /dev/sdd5
2 8 21 2 active sync /dev/sdb5
3 8 5 3 active sync /dev/sda5
4 8 101 4 active sync /dev/sdg5Do I need to specifically shrink devid 3 (it looks like after a reboot the array in question is now md125)??
btrfs filesystem resize 3:-5t /data
I've picked 5Tb to be on the safe size - the array is the 5 4TB differences between 10TB and 14TB.
I would then proceed with:
mdadm /dev/md125 --fail --verbose /dev/sdg5 mdadm /dev/md125 --remove --verbose /dev/sdg5 mdadm --zero-superblock --verbose /dev/sdg5 mdadm --grow /dev/md125 --array-size 1171743012 mdadm --grow /dev/md125 --raid-devices=4 --backup-file=/backupfile mdadm --grow /dev/md125 --raid-devices=5 --level=6 --add /dev/sdg5
Can the last two commands be combined (ie. can you miss the --raid-devices=4 line and just run the last line??)
Does this sound about right??
Thanks
Andy
powellandy1 wrote:
StephenB wrote:
powellandy1 wrote:
So what exactly does the XRAID/FlexRAID toggle button in the GUI actually change??
In XRAID mode, the system automatically expands when new disks are added (or when smaller disks are replaced with larger ones).
If FlexRAID mode, you need to do all steps manually - creating RAID groups, or adding new disks to the appropriate RAID groups, and concatenating the RAID groups together.
I understand that - is XRAID literally a boolean flag?? Is it automatically determined (by a set of rules) when the RAID system is in a state that it can automatically expanded??
I don't understand what you are stuck on. Perhaps you are overthinking it?
- XRAID is a mode where the system uses an algorithm to automatically add or modify RAID groups as disks are added or upgraded. That expands the volume size (or in some cases switches to dual redundancy). In your case, that algorithm didn't work correctly.
- FlexRAID is a mode where the user manually adds or modifies the RAID groups. It also allows users to use RAID structures that the XRAID algorithm can't handle.
Your question "Is it automatically determined..." makes no sense to me. The system doesn't spontaneously shift between the XRAID and FlexRAID modes. You choose the mode, and the system stays in that mode until you change it. However, since FlexRAID includes structures that XRAID can't handle, the system sometimes won't let you change from FlexRAID to XRAID.
Thanks StephenB
Your question "Is it automatically determined..." makes no sense to me. The system doesn't spontaneously shift between the XRAID and FlexRAID modes. You choose the mode, and the system stays in that mode until you change it. However, since FlexRAID includes structures that XRAID can't handle, the system sometimes won't let you change from FlexRAID to XRAID.
This is what I was after. There are some posts in the forum that suggest once you go to FlexRAID you can never go back again - and I was just trying to understand why - but you have clarified we can go back (assuming the structure can be handled by XRAID).
I'm running an experiment currently - 6x6TB was RAID5. I've resized FS, failed and removed last disk, currently rebuilding. Will then try and grow into RAID6. I haven't turned XRAID off. Will report back.
powellandy1 wrote:
Thanks StephenB
Your question "Is it automatically determined..." makes no sense to me. The system doesn't spontaneously shift between the XRAID and FlexRAID modes. You choose the mode, and the system stays in that mode until you change it. However, since FlexRAID includes structures that XRAID can't handle, the system sometimes won't let you change from FlexRAID to XRAID.
This is what I was after. There are some posts in the forum that suggest once you go to FlexRAID you can never go back again - and I was just trying to understand why - but you have clarified we can go back (assuming the structure can be handled by XRAID).
I'm running an experiment currently - 6x6TB was RAID5. I've resized FS, failed and removed last disk, currently rebuilding. Will then try and grow into RAID6. I haven't turned XRAID off. Will report back.
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