on May 1st it threw one 'medium error' but it has been throwing many errors (for the same sector) since.
syslog:May 6 19:07:07 ms-be2043 kernel: [1663397.029420] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog:May 6 19:07:07 ms-be2043 kernel: [1663397.143311] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog:May 6 19:07:07 ms-be2043 kernel: [1663397.233289] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:10:13 ms-be2043 kernel: [1299957.031634] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:10:13 ms-be2043 kernel: [1299957.071272] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:10:13 ms-be2043 kernel: [1299957.124340] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:10:13 ms-be2043 kernel: [1299957.161142] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:17:48 ms-be2043 kernel: [1300412.076706] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:17:48 ms-be2043 kernel: [1300412.122724] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:17:48 ms-be2043 kernel: [1300412.171265] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:18:31 ms-be2043 kernel: [1300454.365840] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:18:31 ms-be2043 kernel: [1300454.425160] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:18:31 ms-be2043 kernel: [1300454.469737] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:18:31 ms-be2043 kernel: [1300454.519819] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:18:31 ms-be2043 kernel: [1300455.129463] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:18:42 ms-be2043 kernel: [1300466.079200] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:18:42 ms-be2043 kernel: [1300466.147393] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:18:42 ms-be2043 kernel: [1300466.188098] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:18:43 ms-be2043 kernel: [1300466.228179] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:18:43 ms-be2043 kernel: [1300466.263569] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:18:43 ms-be2043 kernel: [1300466.301320] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:18:43 ms-be2043 kernel: [1300466.348356] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:18:43 ms-be2043 kernel: [1300466.382976] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:18:43 ms-be2043 kernel: [1300466.424650] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:18:43 ms-be2043 kernel: [1300466.465320] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:19:28 ms-be2043 kernel: [1300511.565577] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:37:52 ms-be2043 kernel: [1301616.143616] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:37:55 ms-be2043 kernel: [1301619.220298] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:37:56 ms-be2043 kernel: [1301619.323860] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:37:56 ms-be2043 kernel: [1301619.804557] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:45:17 ms-be2043 kernel: [1302060.817209] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:45:54 ms-be2043 kernel: [1302097.933325] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:45:54 ms-be2043 kernel: [1302097.972084] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:45:54 ms-be2043 kernel: [1302098.010523] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:46:02 ms-be2043 kernel: [1302106.211823] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:53:31 ms-be2043 kernel: [1302555.164794] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:53:31 ms-be2043 kernel: [1302555.263114] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:53:31 ms-be2043 kernel: [1302555.346404] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:55:06 ms-be2043 kernel: [1302649.635148] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:55:06 ms-be2043 kernel: [1302649.674508] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:55:06 ms-be2043 kernel: [1302649.721117] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 14:58:27 ms-be2043 kernel: [1302850.729533] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 15:00:23 ms-be2043 kernel: [1302967.263219] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 15:00:23 ms-be2043 kernel: [1302967.301453] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 15:00:23 ms-be2043 kernel: [1302967.339690] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.4.gz:May 2 15:01:43 ms-be2043 kernel: [1303046.686366] blk_update_request: I/O error, dev sdd, sector 4432735456 syslog.5.gz:May 1 18:07:30 ms-be2043 kernel: [1227788.892047] blk_update_request: I/O error, dev sdd, sector 4432735456
Not sure if there's a usual procedure we have here. Does writing 0s over that sector (in an attempt to get the drive firmware to remap it), and then if successful, making a fresh filesystem on the disk (and then letting replication do its thing) make sense?