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jonp

Ability to remove drive from array without having to destroy parity

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Would this also include the ability to replace a drive without having to rebuild parity?

 

For example, if I want to replace an existing drive with a bigger drive (including the parity drive) it would be great if we could just add the new drive and tell unRaid that it was to replace an existing drive. UnRaid could then clone the existing drive over to the new drive (whilst not destroying parity) and once complete, automatically remove the old drive from the array. The key thing here is that while the clone operation takes place, any parity calculations include the clone pair as a single drive rather than as two separate drives.

 

Hopefully the above makes sense. If this isn't included in this feature, please can you move this post to a new feature request?

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Would this also include the ability to replace a drive without having to rebuild parity?

 

For example, if I want to replace an existing drive with a bigger drive (including the parity drive) it would be great if we could just add the new drive and tell unRaid that it was to replace an existing drive. UnRaid could then clone the existing drive over to the new drive (whilst not destroying parity) and once complete, automatically remove the old drive from the array. The key thing here is that while the clone operation takes place, any parity calculations include the clone pair as a single drive rather than as two separate drives.

 

Hopefully the above makes sense. If this isn't included in this feature, please can you move this post to a new feature request?

Replacing a drive with a bigger drive without breaking parity is already available and has been for a very long time.  During this process the array is actually unprotected, but as long as you still have the old drive you can still revert to the protected state if anything goes wrong.  I am not sure that your idea of having the old drive and the new one both plugged in and cloning actually adds any significant value, and it seems it could add a lot of unnecessary complexity.

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Would this also include the ability to replace a drive without having to rebuild parity?

 

For example, if I want to replace an existing drive with a bigger drive (including the parity drive) it would be great if we could just add the new drive and tell unRaid that it was to replace an existing drive. UnRaid could then clone the existing drive over to the new drive (whilst not destroying parity) and once complete, automatically remove the old drive from the array. The key thing here is that while the clone operation takes place, any parity calculations include the clone pair as a single drive rather than as two separate drives.

 

Hopefully the above makes sense. If this isn't included in this feature, please can you move this post to a new feature request?

Replacing a drive with a bigger drive without breaking parity is already available and has been for a very long time.  During this process the array is actually unprotected, but as long as you still have the old drive you can still revert to the protected state if anything goes wrong.  I am not sure that your idea of having the old drive and the new one both plugged in and cloning actually adds any significant value, and it seems it could add a lot of unnecessary complexity.

(Commenting on bolded section] So long as you refrain from writing to the disk being rebuilt during its reconstruction process.

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My understanding is that to replace a drive you remove the old one and insert the new one and allow unraid to rebuild it from the parity calculations. Please let me know if this isn't the correct way of doing it currently because I'm about to do it and I don't want to make mistakes! :-)

 

If my understanding above is correct (and from your comment 'the array is actually unprotected' I assume it is) then I think what I'm looking for is a way to do it without leaving the array unprotected during the process. Not being familiar with the internals on unRaid I have no idea if this would add a significant amount of complexity over and above what is already planned for this feature (removing a drive) and so I asked if it would be possible to include it. I know that it is not an essential feature (or else it would be in already), but being able to upgrade drives without leaving the array unprotected for a period of time would be a big plus for users such as myself who are less skilled/confident in such matters.

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You are talking about replacing a drive. We are talking about removing a drive (i.e. reducing the drive count in the server by one).

 

You have a right to be confused though as we touched on a lot of things namely my opinion that to upgrade  a drive you should not just pull one and have it rebuilt. For me this is a bad thing as it puts the system into a failed state for potentially a whole day+ in which time any real drive failure will result in data loss.

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You are talking about replacing a drive. We are talking about removing a drive (i.e. reducing the drive count in the server by one).

 

Ok, I'll raise this as a separate feature request then. Thanks for the clarification :-)

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Just curious if this is being worked on or at least actively considered.

 

I raise it again as I am currently embarking on a new disk refresh and upgrade (3rd since we started discussing this) and it still maintain that this would both be a genuinely useful / time saving feature but also a Unique Selling Point that your competitors simply cant offer (due to the nature of the RAID they use) should be grabbed with both hands IMHO

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Bumping this thread again to see if there are any plans to implement in the near future. 

 

I've had my server running extremely well for around a decade now (pre-4.7) and as a result, have some smaller disks I would prefer to phase out completely, reducing my disk count, rather than replace. I'm aware there are ways to do this but I'd currently require some assistance from the forums to make sure I don't break anything (i.e. rsync/move data on to alternate disk, remove, rebuild parity). 

 

The idea of being able to 'decomission' a disk seems like a great idea. 

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