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Add an option to choose the btrfs raid profile for cache disks


Sunri5e

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Currently you have raid1 as only raid-profile option for the cache disks.

 

It would be nice, if you can choose between all possible btrfs raid-profiles.

 

Examples:

 

2 x 250GB SSDs:

 

raid1-profile:

full Capacity: 250GB, but safety.

 

raid0-profile:

full Capacity: 500GB, no safety.

 

 

OR

 

 

1 x 250GB SSD

1 x 500GB SSD

 

raid1-profile:

full Capacity: 250GB, but safety and 250GB wasted.

 

raid0-profile:

full Capacity: 250GB, no safety and 250GB wasted.

 

single-profile:

full Capacity: 750GB, no safety.

 

 

I have a 250GB and a 500GB SSD, if I want to use the full capacity i have to use the single profile for the data blocks, rather than raid0 but this is not possible, currently.

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Currently you have raid1 as only raid-profile option for the cache disks.

 

It would be nice, if you can choose between all possible btrfs raid-profiles.

 

Examples:

 

2 x 250GB SSDs:

 

raid1-profile:

full Capacity: 250GB, but safety.

 

raid0-profile:

full Capacity: 500GB, no safety.

 

 

OR

 

 

1 x 250GB SSD

1 x 500GB SSD

 

raid1-profile:

full Capacity: 250GB, but safety and 250GB wasted.

 

raid0-profile:

full Capacity: 250GB, no safety and 250GB wasted.

 

single-profile:

full Capacity: 750GB, no safety.

 

 

I have a 250GB and a 500GB SSD, if I want to use the full capacity i have to use the single profile for the data blocks, rather than raid0 but this is not possible, currently.

 

I'm pretty sure it is possible currently, but it involves knowing the right commands for the balance command.

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Not true, it will survive a reboot, it will rebalance to raid1 if you press balance with the default options and possibly if you  add/replace a disk.

 

That's good news. At least once set, it won't randomly switch back unless you mess with it. Did you determine this through your own experience, or has Limetech (or someone else) posted somewhere else that it is persistent?

 

From what Tom posted in the above link, he made it sound like it was not...

 

Note that, at present, the s/w will "revert" the default balance options back to:

-dconvert=raid1 -mconvert=raid1

That is, we don't store your selection.  Similarly if you add a device to an existing pool it will automatically kick off a balance with the default options.  We plan to address this in a future release, but for now you can experiment with it.

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Wish we could do this - I have 2 500g that i would like to make into a 1tb pool (unprotected is fine) for docker/plex storage.

Plex library grows so fast and am about to outgrow a single drive of these older/smaller ones I have laying around....

 

Myk

 

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Not true, it will survive a reboot, it will rebalance to raid1 if you press balance with the default options and possibly if you  add/replace a disk.

 

That's good news. At least once set, it won't randomly switch back unless you mess with it. Did you determine this through your own experience, or has Limetech (or someone else) posted somewhere else that it is persistent?

 

From what Tom posted in the above link, he made it sound like it was not...

 

Note that, at present, the s/w will "revert" the default balance options back to:

-dconvert=raid1 -mconvert=raid1

That is, we don't store your selection.  Similarly if you add a device to an existing pool it will automatically kick off a balance with the default options.  We plan to address this in a future release, but for now you can experiment with it.

 

After reading that 2-3 times I'm pretty sure that what Tom is talking about is the code that shows up on the cache page (that you can modify and run) and that is run when a drive is added to an existing pool (this seems like the bigger issue now...)...

 

Wish we could do this - I have 2 500g that i would like to make into a 1tb pool (unprotected is fine) for docker/plex storage.

Plex library grows so fast and am about to outgrow a single drive of these older/smaller ones I have laying around....

 

Myk

 

 

Are you having Plex make thumbnails, or do you just have that much media?

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I used a bunch of options, like raid0, raid5 and raid6, once set they all remain like that, including after rebooting.

 

Great! Thanks for the feedback!

 

Hmmm.... Makes me think maybe I don't need a brand new giant SSD cache drive... I could repurpose a few older small ones and "combine" them together with raid0...

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