Adding mirrors to Veritas Volume Manager volumes

One of the cool features of Veritas Volume Manager (VxVM) is it’s ability to change the layout of a volume on the fly with vxasssist(1m). This option has helped me numerous times, especially when I needed to mirror volumes that weren’t mirrored. Given the following unmirrored striped volume:
$ vxprint -hft

Disk group: oradg

DG NAME         NCONFIG      NLOG     MINORS   GROUP-ID
ST NAME         STATE        DM_CNT   SPARE_CNT         APPVOL_CNT
DM NAME         DEVICE       TYPE     PRIVLEN  PUBLEN   STATE
RV NAME         RLINK_CNT    KSTATE   STATE    PRIMARY  DATAVOLS  SRL
RL NAME         RVG          KSTATE   STATE    REM_HOST REM_DG    REM_RLNK
CO NAME         CACHEVOL     KSTATE   STATE
VT NAME         NVOLUME      KSTATE   STATE
V  NAME         RVG/VSET/CO  KSTATE   STATE    LENGTH   READPOL   PREFPLEX UTYPE
PL NAME         VOLUME       KSTATE   STATE    LENGTH   LAYOUT    NCOL/WID MODE
SD NAME         PLEX         DISK     DISKOFFS LENGTH   [COL/]OFF DEVICE   MODE
SV NAME         PLEX         VOLNAME  NVOLLAYR LENGTH   [COL/]OFF AM/NM    MODE
SC NAME         PLEX         CACHE    DISKOFFS LENGTH   [COL/]OFF DEVICE   MODE
DC NAME         PARENTVOL    LOGVOL
SP NAME         SNAPVOL      DCO

dg oradg        default      default  10000    1127240283.19.winnie

dm c1t1d0       c1t1d0s2     auto     2048     35521408 -
dm c1t2d0       c1t2d0s2     auto     2048     35521408 -
dm c1t3d0       c1t3d0s2     auto     2048     35521408 -
dm c1t4d0       c1t4d0s2     auto     2048     35365968 -
dm c1t5d0       c1t5d0s2     auto     2048     35521408 -
dm c1t6d0       c1t6d0s2     auto     2048     35521408 -

v  oravol01     -            ENABLED  ACTIVE   20971520 SELECT    oravol01-01 fsgen
pl oravol01-01  oravol01     ENABLED  ACTIVE   20971776 STRIPE    3/128    RW
sd c1t1d0-01    oravol01-01  c1t1d0   0        6990592  0/0       c1t1d0   ENA
sd c1t2d0-01    oravol01-01  c1t2d0   0        6990592  1/0       c1t2d0   ENA
sd c1t3d0-01    oravol01-01  c1t3d0   0        6990592  2/0       c1t3d0   ENA

We can easily add a mirror by invoking vxassist(1m) with the “mirror” option:
$ vxassist mirror oravol01 layout=stripe ncol=3 &
The mirror option accepts a layout option and several keywords to control the layout of the new mirror. In this example we used a 3-column striped plex to match the layout of the existing plex. After the mirror operation completes, the volume will contain a second plex (the mirror) that matches the original:
$ vxprint -hft

Disk group: oradg

DG NAME         NCONFIG      NLOG     MINORS   GROUP-ID
ST NAME         STATE        DM_CNT   SPARE_CNT         APPVOL_CNT
DM NAME         DEVICE       TYPE     PRIVLEN  PUBLEN   STATE
RV NAME         RLINK_CNT    KSTATE   STATE    PRIMARY  DATAVOLS  SRL
RL NAME         RVG          KSTATE   STATE    REM_HOST REM_DG    REM_RLNK
CO NAME         CACHEVOL     KSTATE   STATE
VT NAME         NVOLUME      KSTATE   STATE
V  NAME         RVG/VSET/CO  KSTATE   STATE    LENGTH   READPOL   PREFPLEX UTYPE
PL NAME         VOLUME       KSTATE   STATE    LENGTH   LAYOUT    NCOL/WID MODE
SD NAME         PLEX         DISK     DISKOFFS LENGTH   [COL/]OFF DEVICE   MODE
SV NAME         PLEX         VOLNAME  NVOLLAYR LENGTH   [COL/]OFF AM/NM    MODE
SC NAME         PLEX         CACHE    DISKOFFS LENGTH   [COL/]OFF DEVICE   MODE
DC NAME         PARENTVOL    LOGVOL
SP NAME         SNAPVOL      DCO

dg oradg        default      default  10000    1127240283.19.winnie

dm c1t1d0       c1t1d0s2     auto     2048     35521408 -
dm c1t2d0       c1t2d0s2     auto     2048     35521408 -
dm c1t3d0       c1t3d0s2     auto     2048     35521408 -
dm c1t4d0       c1t4d0s2     auto     2048     35365968 -
dm c1t5d0       c1t5d0s2     auto     2048     35521408 -
dm c1t6d0       c1t6d0s2     auto     2048     35521408 -

v  oravol01     -            ENABLED  ACTIVE   20971520 SELECT    -        fsgen
pl oravol01-01  oravol01     ENABLED  ACTIVE   20971776 STRIPE    3/128    RW
sd c1t1d0-01    oravol01-01  c1t1d0   0        6990592  0/0       c1t1d0   ENA
sd c1t2d0-01    oravol01-01  c1t2d0   0        6990592  1/0       c1t2d0   ENA
sd c1t3d0-01    oravol01-01  c1t3d0   0        6990592  2/0       c1t3d0   ENA
pl oravol01-02  oravol01     ENABLED  ACTIVE   20971776 STRIPE    3/128    RW
sd c1t4d0-01    oravol01-02  c1t4d0   0        6990592  0/0       c1t4d0   ENA
sd c1t5d0-01    oravol01-02  c1t5d0   0        6990592  1/0       c1t5d0   ENA
sd c1t6d0-01    oravol01-02  c1t6d0   0        6990592  2/0       c1t6d0   ENA

Veritas makes managing storage a snap!