I think your disk is to be replaced.
syserrlg buffer overflow means that error event were sent so quickly that not all of them could be logged by errdaemon because of "buffer overflow".
The buffer size can be increased (and it is recommended action linked to the error) but I am sure the error disappeare when you exchange/remove borken disk.
regards, m.
And here is the switch of errdaemon which lets increase the buffer:
-B BufferSize Uses the number of bytes specified by the BufferSize parameter for the error log device driver's in-memory buffer. The specified buffer size is saved in the error log configuration database. If the BufferSize parameter is larger than the buffer size currently in use, the in-memory buffer is immediately increased. If the BufferSize parameter is smaller than the buffer size currently in use, the new size is put into effect the next time the error logging daemon is started after the system is rebooted. The buffer cannot be made smaller than the hard-coded default of 8KB.
If this parameter is not specified, the error logging daemon uses the buffer size from the error log configuration database.
The size you specify is rounded up to the next integral multiple of the memory page size (4KB). The memory used for the error log device driver's in-memory buffer is not available for use by other processes. (The buffer is pinned). Be careful not to impact your system's performance by making the buffer excessively large. On the other hand, if you make the buffer too small, the buffer can become full if error entries arrive faster than they can be read from the buffer and put into the log file. When the buffer is full, new entries are discarded until space becomes available in the buffer. When this situation occurs, the error logging daemon creates an error log entry to inform you of the problem. You can correct the problem by enlarging the buffer.
