Reserving disks in VxVm

70.1    Setting Reservation On
By default, the vxassist command allocates space from any disk that has free space. You can reserve a set of disks for special purposes, such as to avoid general use of a particularly slow or a particularly fast disk.
To reserve a disk for special purposes, use the following command:

# vxedit -g testdg set reserve=on disk01

indhost# vxdisksetup -i TagmaStore-USP0_1
indhost# vxdisksetup -i TagmaStore-USP1_0
indhost# vxdg init testdg disk01=TagmaStore-USP0_1
indhost# vxdg -g testdg adddisk disk02=TagmaStore-USP1_0
indhost# vxedit -g testdg set reserve=on disk01
indhost# vxassist -g testdg make testvol 500M
indhost# vxprint -ht testvol
Disk group: testdg

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
EX NAME         ASSOC        VC                       PERMS    MODE     STATE
SR NAME         KSTATE

v  testvol      -            ENABLED  ACTIVE   1024000  SELECT    -        fsgen
pl testvol-01   testvol      ENABLED  ACTIVE   1024000  CONCAT    -        RW
sd disk02-01    testvol-01   disk02   0        1024000  0         TagmaStore-USP1_0 ENA

After you enter this command, the vxassist program does not allocate space from the selected disk (disk01) unless that disk is specifically mentioned on the vxassist command line. For example, if disk01 is reserved, use the following command:

indhost# vxassist -g testdg make testvol 500M disk01
indhost# vxprint -th testvol
Disk group: testdg

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
EX NAME         ASSOC        VC                       PERMS    MODE     STATE
SR NAME         KSTATE

v  testvol      -            ENABLED  ACTIVE   1024000  SELECT    -        fsgen
pl testvol-01   testvol      ENABLED  ACTIVE   1024000  CONCAT    -        RW
sd disk01-02    testvol-01   disk01   1024000  1024000  0         TagmaStore-USP0_1 ENA

The vxassist command overrides the reservation and creates a 500 megabyte volume on testdg.

70.2    To turn off reservation of a disk

indhost# vxedit -g testdg set reserve=off disk01
indhost# vxassist -g testdg remove volume testvol
indhost# vxassist -g testdg make testvol 500M
indhost# vxprint -ht testvol
Disk group: testdg

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
EX NAME         ASSOC        VC                       PERMS    MODE     STATE
SR NAME         KSTATE

v  testvol      -            ENABLED  ACTIVE   1024000  SELECT    -        fsgen
pl testvol-01   testvol      ENABLED  ACTIVE   1024000  CONCAT    -        RW
sd disk02-01    testvol-01   disk02   0        1024000  0         TagmaStore-USP1_0 ENA