Un disk group non è altro che un contenitore dove sono presenti delle entità, nel caso concreto queste entità sono dei dischi.
All'interno del diskgroup è possibile definire dei volumi, parti del diskgroup, utilizzandoli poi per la memorizzazione dei dati.
Dapprima vanno individuati i dischi con cui creare il diskgroup.
Supponiamo di avere quindi 4 dischi da poter utilizzare. Per verificare i dischi presenti sulla macchina possiamo utilizzare il comando "vxdisk list".
Nell'esempio seguente ho utilizzato il comando nella seguente sintassi: "vxdisk -o alldgs list", che permette di visualizzare anche i diskgroup, che in quel momento non appartengono al server; ci troviamo in un'architettura in cluster.
c3t32d0s2 sliced - - online
c3t33d0s2 sliced - - online
c9t32d0s2 sliced - - online
c9t33d0s2 sliced - - online
Lanciamo quindi il comando vxdiskadm, si presenterà un'interfaccia testuale del genere:
Volume Manager Support Operations
Menu: VolumeManager/Disk
1 Add or initialize one or more disks
2 Encapsulate one or more disks
3 Remove a disk
4 Remove a disk for replacement
5 Replace a failed or removed disk
6 Mirror volumes on a disk
7 Move volumes from a disk
8 Enable access to (import) a disk group
9 Remove access to (deport) a disk group
10 Enable (online) a disk device
11 Disable (offline) a disk device
12 Mark a disk as a spare for a disk group
13 Turn off the spare flag on a disk
list List disk information
? Display help about menu
?? Display help about the menuing system
q Exit from menus
Select an operation to perform:
selezionare 1(uno) per l'inizializzazione dei dischi, tenete presente che se i disk group non è presente ne verrà creato uno nuovo con il nome specificato.
Add or initialize disks
Menu: VolumeManager/Disk/AddDisks
Use this operation to add one or more disks to a disk group. You can
add the selected disks to an existing disk group or to a new disk group
that will be created as a part of the operation. The selected disks may
also be added to a disk group as spares. The selected disks may also
be initialized without adding them to a disk group leaving the disks
available for use as replacement disks.
More than one disk or pattern may be entered at the prompt. Here are
some disk selection examples:
all: all disks
c3 c4t2: all disks on both controller 3 and controller 4, target 2
c3t4d2: a single disk
Select disk devices to add: [<pattern-list>,all,list,q,?] c3t32d0 c3t33d0 c9t32d0 c9t33d0
Here are the disks selected. Output format: [Device_Name]
c3t32d0 c3t33d0 c9t32d0 c9t33d0
Continue operation? [y,n,q,?] (default: y)
You can choose to add these disks to an existing disk group, a
new disk group, or you can leave these disks available for use
by future add or replacement operations. To create a new disk
group, select a disk group name that does not yet exist. To
leave the disks available for future use, specify a disk group
name of "none".
Which disk group [<group>,none,list,q,?] (default: rootdg) testdg
There is no active disk group named testdg.
Create a new group named testdg? [y,n,q,?] (default: y)
Use default disk names for these disks? [y,n,q,?] (default: y)
Add disks as spare disks for testdg? [y,n,q,?] (default: n)
A new disk group will be created named testdg and the selected disks
will be added to the disk group with default disk names.
c3t32d0 c3t33d0 c9t32d0 c9t33d0
Continue with operation? [y,n,q,?] (default: y)
The following disk devices appear to have been initialized already.
The disks are currently available as replacement disks.
Output format: [Device_Name]
c3t32d0 c3t33d0 c9t32d0 c9t33d0
Use these devices? [Y,N,S(elect),q,?] (default: Y)
The following disks you selected for use appear to already have
been initialized for the Volume Manager. If you are certain the
disks already have been initialized for the Volume Manager, then
you do not need to reinitialize these disk devices.
Output format: [Device_Name]
c3t32d0 c3t33d0 c9t32d0 c9t33d0
Reinitialize these devices? [Y,N,S(elect),q,?] (default: Y)
Initializing device c3t32d0.
Initializing device c3t33d0.
Initializing device c9t32d0.
Initializing device c9t33d0.
Creating a new disk group named testdg containing the disk
device c3t32d0 with the name testdg01.
Adding disk device c3t33d0 to disk group testdg with disk
name testdg02.
Adding disk device c9t32d0 to disk group testdg with disk
name testdg03.
Adding disk device c9t33d0 to disk group testdg with disk
name testdg04.
Add or initialize other disks? [y,n,q,?] (default: n)
A questo punto abbiamo creato il nostro diskgroup con il nome testdg, per visualizzare la sua struttura basta utilizzare il comando vxprint
vxprint -ht -g testdg
DG NAME NCONFIG NLOG MINORS GROUP-ID
DM NAME DEVICE TYPE PRIVLEN PUBLEN STATE
V NAME USETYPE KSTATE STATE LENGTH READPOL PREFPLEX
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
dg testdg default default 129000 1144421907.10833.aagg02
dm testdg01 c3t32d0s2 sliced 2888 71124291 -
dm testdg02 c3t33d0s2 sliced 2888 71124291 -
dm testdg03 c9t32d0s2 sliced 2888 71124291 -
dm testdg04 c9t33d0s2 sliced 2888 71124291 -