We found that a disk was dead. The disk was hotswap so we replaced the drive,
and then, ....

Note:  I didn't know the `lssf` command when these notes were written, but try it.


jstile /home/jstile >>ioscan -fnC disk
Class     I  H/W Path     Driver      S/W State H/W Type  Description
======================================================================
disk      3  8/8.1.0      sdisk       CLAIMED   DEVICE    SEAGATE ST34572WC
                         /dev/dsk/c0t1d0   /dev/rdsk/c0t1d0
disk      4  8/8.2.0      sdisk       CLAIMED   DEVICE    SEAGATE ST34572WC
                         /dev/dsk/c0t2d0   /dev/rdsk/c0t2d0
disk      5  8/8.3.0      sdisk       CLAIMED   DEVICE    SEAGATE ST34572WC
                         /dev/dsk/c0t3d0   /dev/rdsk/c0t3d0
disk      6  8/8.4.0      sdisk       CLAIMED   DEVICE    SEAGATE ST34572WC
                         /dev/dsk/c0t4d0   /dev/rdsk/c0t4d0
disk      7  8/8.5.0      sdisk       CLAIMED   DEVICE    SEAGATE ST34572WC
                         /dev/dsk/c0t5d0   /dev/rdsk/c0t5d0
disk      8  8/8.6.0      sdisk       CLAIMED   DEVICE    SEAGATE ST34572WC
                         /dev/dsk/c0t6d0   /dev/rdsk/c0t6d0
disk      9  8/8.8.0      sdisk       CLAIMED   DEVICE    SEAGATE ST34572WC
                         /dev/dsk/c0t8d0   /dev/rdsk/c0t8d0
disk     10  8/8.9.0      sdisk       CLAIMED   DEVICE    SEAGATE ST34572WC
                         /dev/dsk/c0t9d0   /dev/rdsk/c0t9d0
disk     11  8/8.10.0     sdisk       CLAIMED   DEVICE    SEAGATE ST34572WC
                         /dev/dsk/c0t10d0   /dev/rdsk/c0t10d0
disk     12  8/8.15.0     sdisk       CLAIMED   DEVICE    SEAGATE ST34572WC
                         /dev/dsk/c0t15d0   /dev/rdsk/c0t15d0
disk     13  8/12.1.0     sdisk       CLAIMED   DEVICE    SEAGATE ST34572WC
                         /dev/dsk/c1t1d0   /dev/rdsk/c1t1d0
disk     14  8/12.2.0     sdisk       CLAIMED   DEVICE    SEAGATE ST34572WC
                         /dev/dsk/c1t2d0   /dev/rdsk/c1t2d0
disk     15  8/12.3.0     sdisk       CLAIMED   DEVICE    SEAGATE ST34572WC
                         /dev/dsk/c1t3d0   /dev/rdsk/c1t3d0
disk     22  8/12.4.0     sdisk       CLAIMED   DEVICE    SEAGATE ST34572WC
                         /dev/dsk/c1t4d0   /dev/rdsk/c1t4d0
disk     16  8/12.5.0     sdisk       CLAIMED   DEVICE    SEAGATE ST34572WC
                         /dev/dsk/c1t5d0   /dev/rdsk/c1t5d0
disk     17  8/12.6.0     sdisk       CLAIMED   DEVICE    SEAGATE ST34572WC
                         /dev/dsk/c1t6d0   /dev/rdsk/c1t6d0
disk     18  8/12.8.0     sdisk       CLAIMED   DEVICE    SEAGATE ST34572WC
                         /dev/dsk/c1t8d0   /dev/rdsk/c1t8d0
disk     19  8/12.9.0     sdisk       CLAIMED   DEVICE    SEAGATE ST34572WC
                         /dev/dsk/c1t9d0   /dev/rdsk/c1t9d0
disk     20  8/12.10.0    sdisk       CLAIMED   DEVICE    SEAGATE ST34572WC
                         /dev/dsk/c1t10d0   /dev/rdsk/c1t10d0
disk     21  8/12.15.0    sdisk       CLAIMED   DEVICE    SEAGATE ST34572WC
                         /dev/dsk/c1t15d0   /dev/rdsk/c1t15d0
disk      0  10/0.5.0     sdisk       CLAIMED   DEVICE    SEAGATE ST34371W
                         /dev/dsk/c2t5d0   /dev/rdsk/c2t5d0
disk      1  10/0.6.0     sdisk       CLAIMED   DEVICE    SEAGATE ST34371W
                         /dev/dsk/c2t6d0   /dev/rdsk/c2t6d0
disk      2  10/12/5.2.0  sdisk       CLAIMED   DEVICE    TOSHIBA CD-ROM XM-5701TA
                         /dev/cdrom        /dev/dsk/c4t2d0   /dev/rdsk/c4t2d0

jstile /home/jstile >>diskinfo /dev/rdsk/c1t4d0
SCSI describe of /dev/rdsk/c1t4d0:
             vendor: SEAGATE 
         product id: ST34572WC       
               type: direct access
               size: 4194157 Kbytes
   bytes per sector: 512

jstile /home/jstile >>vgcfgrestore -n /dev/vg01 -l
Volume Group Configuration information in "/etc/lvmconf/vg01.conf"
VG Name /dev/vg01
 ---- Physical volumes : 12 ----
    /dev/rdsk/c0t1d0 (Non-bootable)
    /dev/rdsk/c0t2d0 (Non-bootable)
    /dev/rdsk/c0t3d0 (Non-bootable)
    /dev/rdsk/c0t4d0 (Non-bootable)
    /dev/rdsk/c0t5d0 (Non-bootable)
    /dev/rdsk/c0t6d0 (Non-bootable)
    /dev/rdsk/c1t1d0 (Non-bootable)
    /dev/rdsk/c1t2d0 (Non-bootable)
    /dev/rdsk/c1t3d0 (Non-bootable)
    /dev/rdsk/c1t4d0 (Non-bootable)
    /dev/rdsk/c1t5d0 (Non-bootable)
    /dev/rdsk/c1t6d0 (Non-bootable)
    
jstile /home/jstile >>vgcfgrestore -n /dev/vg01 /dev/rdsk/c1t4d0
  vgcfgrestore: Couldn't query physical volume "/dev/dsk/c1t4d0":
  The specified path does not correspond to physical volume attached to 
  this volume group
  Volume Group configuration has been restored to /dev/rdsk/c1t4d0

jstile /home/jstile >>strings /etc/lvmtab
/dev/vg00
/dev/dsk/c2t6d0
/dev/dsk/c2t5d0
/dev/dsk/c0t9d0
/dev/dsk/c1t9d0
/dev/vg01
/dev/dsk/c0t1d0
/dev/dsk/c0t2d0
/dev/dsk/c0t3d0
/dev/dsk/c0t4d0
/dev/dsk/c0t5d0
/dev/dsk/c0t6d0
/dev/dsk/c1t1d0
/dev/dsk/c1t2d0
/dev/dsk/c1t3d0
/dev/dsk/c1t4d0
/dev/dsk/c1t5d0
/dev/dsk/c1t6d0
/dev/vg02
/dev/dsk/c0t10d0
/dev/dsk/c0t15d0
/dev/dsk/c1t10d0
/dev/dsk/c1t15d0

vgchange -a y /dev/vg01
  Volume group "/dev/vg01" has been successfully changed.
  
pvdisplay -v /dev/dsk/c1t4d0 |more
  --- Physical volumes ---
  PV Name                     /dev/dsk/c1t4d0
  VG Name                     /dev/vg01
  PV Status                   available    
  Allocatable                 yes          
  VGDA                        2   
  Cur LV                      1      
  PE Size (Mbytes)            4               
  Total PE                    1023    
  Free PE                     0       
  Allocated PE                1023        
  Stale PE                    1023    
  IO Timeout (Seconds)        default 


#Now Resync the mirrors.
lvsync /dev/vg01/lv_datatel