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This mode sets the policy for handling I/O errors on a mounted file system. I/O errors can occur while reading or writing file data or metadata. The file system can respond to these I/O errors either by halting or by gradually degrading. The ioerror option provides five policies that determine how the file system responds to the various errors. All policies limit data corruption, either by stopping the file system or by marking a corrupted inode as bad.
If disable is selected, VxFS disables the file system after detecting any I/O error. You must then unmount the file system and correct the condition causing the I/O error. After the problem is repaired, run fsck and mount the file system again. In most cases, replay fsck to repair the file system. A full fsck is required only in cases of structural damage to the file system's metadata. Select disable in environments where the underlying storage is redundant, such as RAID-5 or mirrored disks.
If nodisable is selected, when VxFS detects an I/O error, it sets the appropriate error flags to contain the error, but continues running. Note that the "degraded" condition indicates possible data or metadata corruption, not the overall performance of the file system.
For file data read and write errors, VxFS sets the VX_DATAIOERR flag in the super-block. For metadata read errors, VxFS sets the VX_FULLFSCK flag in the super-block. For metadata write errors, VxFS sets the VX_FULLFSCK and VX_METAIOERR flags in the super-block and may mark associated metadata as bad on disk. VxFS then prints the appropriate error messages to the console.
See Diagnostic messages.
You should stop the file system as soon as possible and repair the condition causing the I/O error. After the problem is repaired, run fsck and mount the file system again. Select nodisable if you want to implement the policy that most closely resembles the error handling policy of the previous VxFS release.
If wdisable (write disable) or mwdisable (metadata-write disable) is selected, the file system is disabled or degraded, depending on the type of error encountered. Select wdisable or mwdisable for environments where read errors are more likely to persist than write errors, such as when using non-redundant storage. mwdisable is the default ioerror mount option for local mounts.
See the mount_vxfs(1M) manual page.
If mdisable (metadata disable) is selected, the file system is disabled if a metadata read or write fails. However the file system continues to operate if the failure is confined to data extents. mdisable is the default ioerror mount option for cluster mounts.