Hard disk failure on JS12 blade -- MIDRANGE-L

Looks like I am entering the "high maintenance" era on my aging BladeCenter S and my JS12 blade...I see messages in the AMM indicating something is amiss in VIOS:

Blade_01    09/01/18 08:07:11    0x800000ff    OS status (OEMOS Reporting) OS detected fault. See OS error log for details.

Took a look at the error logs on the blade running VIOS and see this:

Detail Data
SYMPTOM CODE
         256
SOFTWARE ERROR CODE
       -9035
ERROR CODE
           0
DETECTING MODULE
'srchevn.c'@line:'234'
FAILING MODULE
rpc.lockd
---------------------------------------------------------------------------
LABEL:          SC_DISK_ERR2
IDENTIFIER:     B6267342

Date/Time:       Sat Sep 1 07:32:05 CDT 2018
Sequence Number: 4972999
Machine Id:      000270CAD400
Node Id:         vios
Class:           H
Type:            PERM
WPAR:            Global
Resource Name:   hdisk1
Resource Class: disk
Resource Type:   scsd
Location:        U78A5.001.WIH1BE8-P1-D1
VPD:
        Manufacturer................IBM-ESXS
        Machine Type and Model......ST9146802SS
        FRU Number..................42D0422
        ROS Level and ID............42353239
        Serial Number...............3NM6QMKN
        EC Level....................H17923Y
        Part Number.................42C0251
        Device Specific.(Z0)........000005329F001002
        Device Specific.(Z1)........0429B529
        Device Specific.(Z2)........1000
        Device Specific.(Z3)........000-0
        Device Specific.(Z4)........0001
        Device Specific.(Z5)........22
        Device Specific.(Z6)........H17923Y

Description
DISK OPERATION ERROR

Probable Causes
DASD DEVICE

Failure Causes
DISK DRIVE
DISK DRIVE ELECTRONICS

        Recommended Actions
        PERFORM PROBLEM DETERMINATION PROCEDURES

Detail Data
PATH ID
           0
SENSE DATA
0600 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0102 0000 7000 0200
0000 0018 0000 0000 0400 0000 0000 0000 0204 0000 FFFF FFFF FFFF FFFF 0000 0000
0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0086 0000
0000 0012 001A

Taking a look at the devices I see some info that I can't quite make full sense of:

$ lsvg -pv rootvg
rootvg:
PV_NAME           PV STATE          TOTAL PPs   FREE PPs    FREE DISTRIBUTION
hdisk0            active            546         440 109..102..11..109..1                        09
hdisk1            missing           546         542 110..105..109..109..                        109

hdisk1 is missing, presumably because it has failed....but I *thought* hdisk0 and hdisk1 were mirrored. I can't seem to find evidence of that. I ran lsdev to check the status:

$ lsdev -type disk
name             status      description
hdisk0           Available   SAS Disk Drive
hdisk1           Available   SAS Disk Drive
..........

Although hdisk1 reports as "missing" it also has a status of "active"...seems a little confusing. I guess active could mean "the power is on and it is spinning".....

And lsvg to see what the volume reports with:

$ lsvg -lv rootvg
rootvg:
LV NAME             TYPE       LPs     PPs     PVs LV STATE MOUNT POINT
hd5                 boot       1       1       1    closed/syncd N/A
hd6                 paging     2       2       1    open/syncd N/A
paging00            paging     4       4       1    open/syncd N/A
hd8                 jfs2log    1       1       1    open/syncd N/A
hd4                 jfs2       1       1       1    open/syncd /
hd2                 jfs2       21      21      1    open/syncd /usr
hd9var              jfs2       3       3       1    open/syncd /var
hd3                 jfs2       14      14      1    open/syncd /tmp
hd1                 jfs2       40      40      1    open/syncd /home
hd10opt             jfs2       13      13      1    open/syncd /opt
hd11admin           jfs2       1       1       1    open/syncd /admin
livedump            jfs2       1       1       1    open/syncd /var/adm/ras/l                        ivedump
lg_dumplv           sysdump    4       4       1    open/syncd N/A
fwdump              jfs2       3       3       1    closed/syncd /var/adm/ras/p                        latform
loglv00             jfslog     1       1       1    closed/syncd N/A

Indications are that the VG isn't a mirrored pair. OR, the mirror has "broken" and I am just seeing the contents of hdisk0....could that be?

I am assuming that the disk HAS failed and needs to be replaced. I ordered a couple of disks (one extrat for backup) and they should be here in about a week. My concern is in properly replacing the failed drive. The fact that it has failed seems to have had no effect on VIOS and I am not "missing" any data. So I think the approach should be to shut down the blade, replace the disk, make sure that it is "seen" by the blade and then add it to the volume group as a mirrored drive. Does that make sense? That *seems* like the way to go. I don't see any exact matches but a couple of IBM support articles seem to be pointing the way:

http://www-01.ibm.com/support/docview.wss?uid=isg3T1000426

http://www-01.ibm.com/support/docview.wss?uid=isg3T1020096

Not many BladeCenter savvy folks on this list but it's worth checking.... Just want to take the correct approach to get the disk replaced.