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How do I know I have a mirror?

khemmerl
Level 5

Apologies for what is probably a basic question:  How do I know I have a mirror?

I set up a disk group and added two disks with the intent that I have the content mirrored between the two.  I don't have any training and the support from the vendor we bought the software from doesn't leave me feeling confident.  I ran the following commands:

 vxdiskadm

Select 1) Add or initialize one or more disks

Select disk devices to add: [<pattern-list>,all,list,q,?] disk_2 disk_3

Continue operation?  y

Which disk group? oraldgbl01

Create a new group named oraldgbl01?  y

Create the disk group as a CDS disk group?  y

Use default disk names for these disks?  n

Add disks as spare disks for oraldgbl01?  n

Exclude disks from hot-relocation use?  n

Add site tag to disks?  n
  A new disk group will be created named oraldgbl01 and the selected disks
  will be added to the disk group with disk names that you will specify
  interactively.

  disk_2 disk_3

Continue with operation?  y
  The following disk devices appear to have been initialized already.
  The disks are currently available as replacement disks.
  Output format: [Device_Name]

  disk_2 disk_3

Use these devices?  Y
  The following disks you selected for use appear to already have
  been initialized for the Volume Manager.
  Please use vxdisk -f init if you want to reinitialize these disks.

Enter disk name for disk_2 [<name>,q,?]  oraldisk1
  VxVM  NOTICE V-5-2-120
Creating a new disk group named oraldgbl01 containing the disk
  device disk_2 with the name oraldisk1.

Enter disk name for disk_3 [<name>,q,?]  oraldisk2
  VxVM  NOTICE V-5-2-88
Adding disk device disk_3 to disk group oraldgbl01 with disk
  name oraldisk2.

Add or initialize other disks?  n

Volume Manager Support Operations
Menu: VolumeManager/Disk

 1      Add or initialize one or more disks
 ...

Select an operation to perform: q

Goodbye.
/> vxassist -g oraldgbl01 make u01 150g
/>
/> mkfs -F vxfs -o bsize=8192,largefiles /dev/vx/rdsk/oraldgbl01/u01
    version 7 layout
    314572800 sectors, 19660800 blocks of size 8192, log size 8192 blocks
    largefiles supported
/>
/> mkdir u01
/>
/> mount -F vxfs -o largefiles /dev/vx/dsk/oraldgbl01/u01 /u01
/> cd /u01
/u01> df -h .
Filesystem             size   used  avail capacity  Mounted on
/dev/vx/dsk/oraldgbl01/u01
                       150G    70M   149G     1%    /u01
/u01>
/u01> vxdisk list
DEVICE       TYPE            DISK         GROUP        STATUS
disk_0       auto:none       -            -            online invalid
disk_1       auto:none       -            -            online invalid
disk_2       auto:cdsdisk    oraldisk1    oraldgbl01   online
disk_3       auto:cdsdisk    oraldisk2    oraldgbl01   online
eva80000_0   auto:cdsdisk    -            -            online
eva80000_1   auto:cdsdisk    -            -            online
eva80000_2   auto:cdsdisk    -            -            online
eva80000_3   auto:cdsdisk    -            -            online
eva80000_4   auto:cdsdisk    -            -            online
eva80000_5   auto:cdsdisk    -            -            online
/u01> vxprint
Disk group: oraldgbl01

TY NAME         ASSOC        KSTATE   LENGTH   PLOFFS   STATE    TUTIL0  PUTIL0
dg oraldgbl01   oraldgbl01   -        -        -        -        -       -

dm oraldisk1    disk_2       -        585846704 -       -        -       -
dm oraldisk2    disk_3       -        585846704 -       -        -       -

v  u01          fsgen        ENABLED  314572800 -       ACTIVE   -       -
pl u01-01       u01          ENABLED  314572800 -       ACTIVE   -       -
sd oraldisk1-01 u01-01       ENABLED  314572800 0       -        -       -
/u01> 

It looks to me like the 150G volume I created is just spanning the two disks and is not actually mirrored on both of them.  Comments?

Ken

1 ACCEPTED SOLUTION

Accepted Solutions

mikebounds
Level 6
Partner Accredited

You do not have a mirror and it does not even span both disks - the volume is entirely on oraldisk1.

You can mirror this onto oraldisk2 using:

 vxassist -g oraldgbl01 mirror u01 oraldisk2

Or you can remove volume and re-create using:

 vxassist -g oraldgbl01 make u01 150g layout=mirror

For a mirror you should see 2 plex records in vxprint so something like:

 

 v  u01          fsgen        ENABLED  314572800 -       ACTIVE   -       -
pl u01-01       u01          ENABLED  314572800 -       ACTIVE   -       -
sd oraldisk1-01 u01-01       ENABLED  314572800 0       -        -
pl u01-02       u01          ENABLED  314572800 -       ACTIVE   -       -
sd oraldisk2-01 u01-01       ENABLED  314572800 0       -        -
You may also see LOG plexes (DRLs) which will say LOGONLY and have a very small size
 
Mike

View solution in original post

4 REPLIES 4

khemmerl
Level 5

"vxprint -ht u01" suggests the volume is not even spread across disk_2 and disk_3 but entirely contained on disk_2:

/u01> vxprint -ht u01
Disk group: oraldgbl01

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  u01          -            ENABLED  ACTIVE   314572800 SELECT   -        fsgen
pl u01-01       u01          ENABLED  ACTIVE   314572800 CONCAT   -        RW
sd oraldisk1-01 u01-01       oraldisk1 0       314572800 0        disk_2   ENA 

mikebounds
Level 6
Partner Accredited

You do not have a mirror and it does not even span both disks - the volume is entirely on oraldisk1.

You can mirror this onto oraldisk2 using:

 vxassist -g oraldgbl01 mirror u01 oraldisk2

Or you can remove volume and re-create using:

 vxassist -g oraldgbl01 make u01 150g layout=mirror

For a mirror you should see 2 plex records in vxprint so something like:

 

 v  u01          fsgen        ENABLED  314572800 -       ACTIVE   -       -
pl u01-01       u01          ENABLED  314572800 -       ACTIVE   -       -
sd oraldisk1-01 u01-01       ENABLED  314572800 0       -        -
pl u01-02       u01          ENABLED  314572800 -       ACTIVE   -       -
sd oraldisk2-01 u01-01       ENABLED  314572800 0       -        -
You may also see LOG plexes (DRLs) which will say LOGONLY and have a very small size
 
Mike

View solution in original post

Gaurav_S
Moderator
Moderator
   VIP    Certified

To check whether you have mirror for a volume, you should see 2 plex (line starts with pl) mainly with the same size (this is important) .... so ideally on a mirrored volume, you would see two plexes with the same size & the overall volume size will be same as well (highlighted below)

 

in the example above:

 

v  u01          fsgen        ENABLED  314572800 -       ACTIVE   -       -
pl u01-01       u01          ENABLED  314572800 -       ACTIVE   -       -
sd oraldisk1-01 u01-01       ENABLED  314572800 0       -        -
pl u01-02       u01          ENABLED  314572800 -       ACTIVE   -       -
sd oraldisk2-01 u01-01       ENABLED  314572800 0       -        -

 

If you want to mirror the existing volume, you can use the commands given by mike above ..

 

G

 

khemmerl
Level 5

That's awesome, thanks.  I ran the following:

 /u01> vxassist -g oraldgbl01 mirror u01 oraldisk2 

And now I see exactly what was expected:

 /u01> vxprint -ht u01
Disk group: oraldgbl01

...

v  u01          -       ENABLED  ACTIVE  314572800 SELECT   -      fsgen
pl u01-01       u01     ENABLED  ACTIVE  314572800 CONCAT   -      RW
sd oraldisk1-01 u01-01  oraldisk1 0      314572800 0        disk_2 ENA
pl u01-02       u01     ENABLED  ACTIVE  314572800 CONCAT   -      RW
sd oraldisk2-01 u01-02  oraldisk2 0      314572800 0        disk_3 ENA