MTA, Conduit and Brightmail Engine services stopped working

Products

• Messaging Gateway

Issue/Introduction

The services MTA, conduit and Brightmail Engine services stopped working on SMG. When trying to activate them from the Web GUI or the CLI, the attempts always fail.
When looking at the messages logs at the time when the issue start occurring, we can  find errors occurring with the Kernel indicating problem with the storage device (sda) causing I/O errors:

 (info) kernel: [-] sd 0:0:0:0: [sda] FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE cmd_age=20s
 (info) kernel: [-] sd 0:0:0:0: [sda] Sense Key : Hardware Error [current] 
 (info) kernel: [-] sd 0:0:0:0: [sda] Add. Sense: No additional sense information
 (info) kernel: [-] sd 0:0:0:0: [sda] CDB: Write(10) 2a 00 0b 3f c6 a0 00 00 08 00
 (err) kernel: [-] blk_update_request: critical target error, dev sda, sector 188728992
 (warning) kernel: [-] EXT4-fs warning (device sda6): ext4_end_bio:302: I/O error -121 writing to inode 5111908 (offset 868352 size 4096 starting block 23591125)
 (err) kernel: [-] Buffer I/O error on device sda6, logical block 18615764
 (info) kernel: [-] sd 0:0:0:0: [sda] FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE cmd_age=20s

Cause

There was a problem with the underlying disk subsystem or corruption of the virtual disk file.

Resolution

This issue can sometimes be addressed by a restart of the Messaging Gateway virtual machine which will cause the filesystems to be checked and repaired.

If a restart of the virtual machine is not successful or does not address the issue, the VM should be reverted to its last good snapsnot or reinstalled.