btrfs or xfs for new server?


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@johnnie.black - If a file is corrupted, it seems you are totally blocked from accessing that file (for partial recovery). Is that true?

 

To others considering what filesystem to use and like this feature, some people run tools that capture md5 or similar checksums with XFS. It's not real time checking, which has advantages and disadvantages. I run something home grown, but there are tools in CA that you can install.

 

When I decided on xfs I was a little concerned that btrfs was not able to report free space accurately. The fact that it was more easily corrupted with a hard shutdown, and did not have nearly the user base of xfs were also factors. Also never realized why it needed ECC memory morso than any other filesystem. All this made me feel it was more fragile than xfs. I'll try beta this and beta that, but for my filesystem I definitely am very very conservative. I was bitten by a file system bug in RFS, that was losing users in droves, and, going forward, I want rock solid with huge install base including production systems. Those guys will make darn sure that the filesystem updates are extremely well tested.

 

I continue to monitor what Johnnie has to say about btrfs, and positive experiences of other users. Have not read horror stories like I was worried would emerge. But I'm sticking with xfs, for now anyway. But I do kick the btrfs tires from time to time.

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48 minutes ago, vinski said:

> is to possible to run a double parity array and to use the second parity drive to fix any failed drive ( ideally remotely until the failed drive is actually replaced) :

   - either use the second parity drive as a replacement data drive

   - keep the remaining parity drive in case of failed parity drive

Is this a manual process ? can it be automated on unRAID ?

 

Yes, you could just run the array with one disabled disk, second parity would protect you from another failure or you could manually unassign the second parity and assign it to the failed disk slot and rebuild.

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42 minutes ago, SSD said:

If a file is corrupted, it seems you are totally blocked from accessing that file (for partial recovery). Is that true?

 

That's how all checksummed filesystem work, including ZFS and ReFS, not sure with those but with btrfs if you can't recover the file from backup you can use btrfs restore to copy the corrupt file.

 

45 minutes ago, SSD said:

Also never realized why it needed ECC memory morso than any other filesystem.

 

You don't, ECC is recommend for anyone who cares about data integrity, but it's not more necessary for btrfs than eg xfs, I think this quote explains it best:

 

Quote

 

Strictly speaking, you don't need ECC memory for either ZFS or BTRFS. ECC memory provides error detection and correction in-memory. It would be ideal to have and use, but not all machines support it.

 

Not having ECC doesn't mean you shouldn't use a filesystem that provides checksums. It will still protect you from disk errors.

 

Car analogy: If you don't have airbags, you still wear your seat belt.

 

 

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7 minutes ago, johnnie.black said:

 

Yes, you could just run the array with one disabled disk, second parity would protect you from another failure or you could manually unassign the second parity and assign it to the failed disk slot and rebuild.

I noted the remotely operated "manual" process of

   - unassignment of second parity

   - assignment of this disk to the failed slot

Can this process be automated on unRAID ?

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  • 3 years later...
10 minutes ago, enjoywithme said:

How to convert BTRFS to XFS without lose data? I have one parity drive, but no extra spare disk. 

Is it possible to unassign the disk and re-format it to XFS, later recovery data via parity synchronizing? 

No. Parity doesn't contain any data, it contains the entire disk, file system and all. If you format a disk, parity will be updated to reflect the change in format and the disk will be empty.

 

You must copy the data elsewhere or restore from backups, you can't convert in place.

 

There is an entire pinned thread and wiki article about file system conversions, it's mostly referencing ReiserFS, but the principles apply to any file system change.

https://wiki.unraid.net/index.php/File_System_Conversion

 

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11 minutes ago, JonathanM said:

No. Parity doesn't contain any data, it contains the entire disk, file system and all. If you format a disk, parity will be updated to reflect the change in format and the disk will be empty.

 

You must copy the data elsewhere or restore from backups, you can't convert in place.

 

There is an entire pinned thread and wiki article about file system conversions, it's mostly referencing ReiserFS, but the principles apply to any file system change.

https://wiki.unraid.net/index.php/File_System_Conversion

 

Thanks. I'm trying the procedure stated in that wiki - move the data out of the driver first and then convert it.

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