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Best way to restore large data to a new mirror?

(@dmccallie)
Active Member Customer

I need to restore ~8TB of data from backup to a new 10TB mirror (two drives for now.)

What is the fastest / most reliable way to do this?  

A) Restore all the data to one of the drives (pre-mirror), and then add the second drive and rebuild the mirror

B) Configure the mirror and then restore the backup to the actual mirror?

Is there a preference?  Thanks.

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Topic starter Posted : 25/11/2021 2:36 pm
(@softraid-support)
Member Admin

Easiest way is create the mirror first, then copy the data to it.

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Posted : 25/11/2021 4:52 pm
(@dmccallie)
Active Member Customer

@softraid-support OK. I need to split the current mirror and use one of it's drives to stage the data to the other drive after turning it into a new mirror.

What happens when I spit my current mirror? Do the two drives stay online, but with different names? At the time of the split, will they both have good copies of their data?

Thanks,

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Topic starter Posted : 25/11/2021 5:13 pm
(@softraid-support)
Member Admin

@dmccallie

Make sure you remove the secondary disk. Copy the data. then when you re-connect, the mirror will properly rebuild.

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Posted : 25/11/2021 6:27 pm
(@dmccallie)
Active Member Customer

@softraid-support  Thanks, but it's more complicated than that. I need to re-partition the new mirror volume, so I think I have to copy from the old partitions to the new (reduced number) of partitions.

Can you tell me how the "read only secondary" drive behaves? Will that drive be accessible (for reading) by the copying program (SuperDuper)? I read somewhere on the forum that the secondary drive is "not mounted" - does that mean it is inaccessible?  If so, can I mount it (under its new name) and then read from it?  Thanks.

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Topic starter Posted : 26/11/2021 11:34 am
(@softraid-support)
Member Admin

@dmccallie

Read Only Secondary is kind of broken at present, so do not use that.

From what I read about your desires, create a one volume mirror, then remove the secondary, connect the backup disk, and copy the data to the new volume (primary disk). You can use SuperDuper just fine.

then when done, remove the backup disk and connect the secondary disk and it will rebuild automatically in the background.

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Posted : 26/11/2021 11:37 am
(@dmccallie)
Active Member Customer

Thanks. It's a bit scary to hear "...kind of broken at present" but I will avoid using secondary read-only!

Can you tell me if this efficient strategy would work?

1) initialize a new 10TB drive as a SoftRaid disk, but not as a RAID 1 disk (not yet.)

2) copy all the data from the active mirror (the one with the old partitions) to the new disk (and into the new partition sizes) using SuperDuper, etc.

3) Delete the active mirror (freeing two drives)

4) Use "Convert Volume" to convert the non-RAID disk (#1 above) into a RAID-1 mirror volume

The advantage (if this works) is that I don't have to rely on my backups (nor add/remove those disks.)

Any issues?

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Topic starter Posted : 26/11/2021 2:05 pm
(@softraid-support)
Member Admin

@dmccallie

I recommend my steps as the most reliable:

remove your other disk and insert the 2 10TB drives.

Create a SoftRAID Mirror.

Use Blink Disk Light to identify the secondary disk. remove that disk. (be slow, so you are not moving it much when rotating/spinning)

Insert your backup. Copy the data.

When done, just insert the secondary disk, it will rebuild in the background.

 

this is the simplest, most reliable way to accomplish your task.

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Posted : 26/11/2021 3:14 pm
(@dmccallie)
Active Member Customer

@softraid-support So I would just remove the secondary disk (slowly) without doing a split mirror operation first?

And then just push it back in when done copying the data, without having to tell it to rebuild?  

Thanks.

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Topic starter Posted : 26/11/2021 3:28 pm
(@softraid-support)
Member Admin

@dmccallie

 

yes

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Posted : 26/11/2021 4:35 pm
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