Btrfs cache raid 0 and raid 1

[SpaceInvaderOne]

Hi i know you can create a raid 1 using

-dconvert=raid0 -mconvert=raid1

 

but is the btrfs raid 1  stripped across both drives giving a faster read off the cache or does it just use the drives normally but not mirrored?

[trurl]

With that setting, the data is raid0 and the metadata is raid1

[SpaceInvaderOne]

With that setting, the data is raid0 and the metadata is raid1

 

ah okay so should I use

-dconvert=raid1 -mconvert=raid1

[trurl]

With that setting, the data is raid0 and the metadata is raid1

 

ah okay so should I use

-dconvert=raid1 -mconvert=raid1

That is the default setting, a raid1 mirror.

[John_M]

Hi i know you can create a raid 1 using

-dconvert=raid0 -mconvert=raid1

 

but is the btrfs raid 1  stripped across both drives giving a faster read off the cache or does it just use the drives normally but not mirrored?

 

I think you might have confused RAID 0 and RAID 1 in your question. It makes much mores sense like this:

 

Hi i know you can create a raid 0 using

-dconvert=raid0 -mconvert=raid1

 

but is the btrfs raid 0  stripped across both drives giving a faster read off the cache or does it just use the drives normally but not mirrored?

 

If that's what you meant then the answer is that the data is striped for speed but the filesystem metadata (which, in comparison, is much smaller) is mirrored for redundancy.

 

[SpaceInvaderOne]

Hi i know you can create a raid 1 using

-dconvert=raid0 -mconvert=raid1

 

but is the btrfs raid 1  stripped across both drives giving a faster read off the cache or does it just use the drives normally but not mirrored?

 

I think you might have confused RAID 0 and RAID 1 in your question. It makes much mores sense like this:

 

Hi i know you can create a raid 0 using

-dconvert=raid0 -mconvert=raid1

 

but is the btrfs raid 0  stripped across both drives giving a faster read off the cache or does it just use the drives normally but not mirrored?

 

If that's what you meant then the answer is that the data is striped for speed but the filesystem metadata (which, in comparison, is much smaller) is mirrored for redundancy.

 

Ha yes thanks thats exactly what i meant. Raid 0. I was wondering if adding a cache drive in raid 0 would give me any kind of performance boost on the cache. Thanks for seeing past my mistake!! What is the advantage of mirroring the files system for redundancy if the data doesnt have redunduncy?

[John_M]

I don't think there's much to be gained from striping the metadata, but added safety from mirroring it.

 

[gundamguy]

What is the advantage of mirroring the files system for redundancy if the data doesnt have redunduncy?

 

In theory it should help recover / prevent file system errors.