Btrfs filesystem goes "read only" after a failed balancing operation
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SUSE Linux Enterprise Server 12
SUSE Linux Enterprise Server 11
This article only covers the situation described in the SUSE knowledgebase article TID 000019789 - During btrfs balance "enospc" errors are reported.
In short the situation is that errors similar to this are seen in the logs:
BTRFS info (device sda1): 1 enospc errors during balance BTRFS info (device sda1): balance: ended with status: -28And subsequently there is an issue mounting the filesystem. In the most severe case this can prevent a boot, particularly if the root filesystem is affected.
For other btrfs mounting/read only errors refer to TID 000019843 - Btrfs Master TID
mount -o remount,rw,skip_balance <mountpoint>
This mount option doesn't prevent balancing entirely, rather it skips automatic resume of an interrupted balance operation.
The operation can later be resumed with btrfs balance resume, or the paused state can be removed with btrfs balance cancel. The default behavior is to resume an interrupted balance immediately after a volume is mounted, which can cause issues for filesystems which encountered enospc issues during balancing and on striped volumes.
Before resuming or attempting a balancing operation, make sure that there is in fact enough space for a balance operation. More information is provided in: TID 000019789 - During btrfs balance "enospc" errors are reported
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- Document ID:000019843
- Creation Date: 27-Jan-2021
- Modified Date:27-Jan-2021
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