root mirroring in solaris-10 using SVM

                      Root mirroring in solaris-10 using SVM

Root mirroring is a useful method in solaris 10 for redundancy and this is a very useful method for live upgrade , where patches are applied in root environment and if any issue is faced system will be booted from mirrored environment. 

Detailed steps

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1. First we need to identify the disks attached for mirroring this can be done using format command , in below case c0d0 and c0d1 are available disks

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bash-3.00# format

Searching for disks...done

AVAILABLE DISK SELECTIONS:

       0. c0d0 <DEFAULT cyl 2085 alt 2 hd 255 sec 63>

          /pci@0,0/pci-ide@1,1/ide@0/cmdk@0,0

       1. c0d1 <DEFAULT cyl 2086 alt 2 hd 255 sec 63>

          /pci@0,0/pci-ide@1,1/ide@0/cmdk@1,0

Specify disk (enter its number): 0

selecting c0d0

Controller working list found

[disk formatted, defect list found]

Warning: Current Disk has mounted partitions.

/dev/dsk/c0d0s0 is currently mounted on /. Please see umount(1M).

/dev/dsk/c0d0s1 is currently used by swap. Please see swap(1M).

FORMAT MENU:

        disk       - select a disk

        type       - select (define) a disk type

        partition  - select (define) a partition table

        current    - describe the current disk

        format     - format and analyze the disk

        fdisk      - run the fdisk program

        repair     - repair a defective sector

        show       - translate a disk address

        label      - write label to the disk

        analyze    - surface analysis

        defect     - defect list management

        backup     - search for backup labels

        verify     - read and display labels

        save       - save new disk/partition definitions

        volname    - set 8-character volume name

        !<cmd>     - execute <cmd>, then return

        quit

format> p (press p)

PARTITION MENU:

        0      - change `0' partition

        1      - change `1' partition

        2      - change `2' partition

        3      - change `3' partition

        4      - change `4' partition

        5      - change `5' partition

        6      - change `6' partition

        7      - change `7' partition

        select - select a predefined table

        modify - modify a predefined partition table

        name   - name the current table

        print  - display the current table

        label  - write partition map and label to the disk

        !<cmd> - execute <cmd>, then return

        quit

partition> p (press p)

Current partition table (original):

Total disk cylinders available: 2085 + 2 (reserved cylinders)

Part      Tag    Flag     Cylinders        Size            Blocks

  0       root    wm     820 - 2084        9.69GB    (1265/0/0) 20322225

  1       swap    wu       3 -  133        1.00GB    (131/0/0)   2104515

  2     backup    wm       0 - 2084       15.97GB    (2085/0/0) 33495525

  3 unassigned    wm       0               0         (0/0/0)           0

  4 unassigned    wm       0               0         (0/0/0)           0

  5 unassigned    wm       0               0         (0/0/0)           0

  6 unassigned    wm       0               0         (0/0/0)           0

  7 unassigned    wm       0               0         (0/0/0)           0

  8       boot    wu       0 -    0        7.84MB    (1/0/0)       16065

  9 alternates    wu       1 -    2       15.69MB    (2/0/0)       32130

In above partition table we can see that 3,4,5,6 are unassigned partitions with in that we can select any partition (in this case i am selecting partition 3)

partition> 3

Part      Tag    Flag     Cylinders        Size            Blocks

  3 unassigned    wm       0               0         (0/0/0)           0

Enter partition id tag[unassigned]:

Enter partition permission flags[wm]:

Enter new starting cyl[0]: 134

Enter partition size[0b, 0c, 134e, 0.00mb, 0.00gb]: 3gb

partition> l

Ready to label disk, continue? yes

partition> p

Current partition table (unnamed):

Total disk cylinders available: 2085 + 2 (reserved cylinders)

Part      Tag    Flag     Cylinders        Size            Blocks

  0       root    wm     820 - 2084        9.69GB    (1265/0/0) 20322225

  1       swap    wu       3 -  133        1.00GB    (131/0/0)   2104515

  2     backup    wm       0 - 2084       15.97GB    (2085/0/0) 33495525

  3 unassigned    wm     134 -  525        3.00GB    (392/0/0)   6297480-------- ( newly created slice) 

  4 unassigned    wm       0               0         (0/0/0)           0

  5 unassigned    wm       0               0         (0/0/0)           0

  6 unassigned    wm       0               0         (0/0/0)           0

  7 unassigned    wm       0               0         (0/0/0)           0

  8       boot    wu       0 -    0        7.84MB    (1/0/0)       16065

  9 alternates    wu       1 -    2       15.69MB    (2/0/0)       32130

2. Secondly we have to create HDD1 partition table same as HDD0

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#prtvtoc /dev/rdsk/c0d0s2 | fmthard -s - /dev/rdsk/c0d1s2

(here from partition table we can see that partition 2 contains full back up of the entire disk and same will be copied to new disk HDD1)

3. create the state database in each disk (here i have choose slice no 7 )

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metadb -afc 3 c0d0s7 c0d1s7

a= add the state database 

f=force (this is needed for HDD0 which is mounted 

c=number of state database in each slice

We can see 3 slices of each disk using below command

bash-3.00# metadb
        flags           first blk       block count
     a m  p  luo        16              8192            /dev/dsk/c0d0s7
     a    p  luo        8208            8192            /dev/dsk/c0d0s7
     a    p  luo        16400           8192            /dev/dsk/c0d0s7
     a    p  luo        16              8192            /dev/dsk/c0d1s7
     a    p  luo        8208            8192            /dev/dsk/c0d1s7
     a    p  luo        16400           8192            /dev/dsk/c0d1s7

4. Initialize each disk
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HDD0

  metainit -f d100 1 1 c0d0s0
  metainit -f d101 1 1 c0d0s1
  metainit -f d103 1 1 c0d0s3

HDD1


  metainit d200 1 1 c0d1s0
  metainit d201 1 1 c0d1s1
  metainit d203 1 1 c0d1s3

5. Initialize the mirrors
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  metainit d0 -m d100
  metainit d1 -m d101
  metainit d3 -m d103

6.Metaroot and editing of /etc/vfstab to boot to our mirror.
********************************************************

 metaroot d0

bash-3.00# cat /etc/vfstab
#device         device          mount           FS      fsck    mount   mount
#to mount       to fsck         point           type    pass    at boot options
#
fd      -       /dev/fd fd      -       no      -
/proc   -       /proc   proc    -       no      -
/dev/md/dsk/d1  -       -       swap    -       no      -
/dev/md/dsk/d0  /dev/md/rdsk/d0 /       ufs     1       no      -
/devices        -       /devices        devfs   -       no      -
sharefs -       /etc/dfs/sharetab       sharefs -       no      -
ctfs    -       /system/contract        ctfs    -       no      -
objfs   -       /system/object  objfs   -       no      -
swap    -       /tmp    tmpfs   -       yes     -
/dev/md/dsk/d3  /dev/md/rdsk/d3 /test1  ufs     2       yes     -


7.Reboot the server

8. Attach the mirror disk using below command

bash-3.00# metattach d0 d200
d0: submirror d200 is attached
bash-3.00# metattach d1 d201
d1: submirror d201 is attached
bash-3.00# metattach d3 d203

(we have to wait till the completion of the sync it is purely depends upon the size of the file system)

d3: submirror d203 is attached

9. Next is we will install the grub in mirrored disk as redundant ( in this case c0d1 is our mirrored disk)

bash-3.00# format
Searching for disks...done


AVAILABLE DISK SELECTIONS:
       0. c0d0 <DEFAULT cyl 2085 alt 2 hd 255 sec 63>
          /pci@0,0/pci-ide@1,1/ide@0/cmdk@0,0
       1. c0d1 <DEFAULT cyl 2085 alt 2 hd 255 sec 63>
          /pci@0,0/pci-ide@1,1/ide@0/cmdk@1,0


bash-3.00# installgrub /boot/grub/stage1 /boot/grub/stage2 /dev/rdsk/c0d1s0
stage1 written to partition 0 sector 0 (abs 16065)
stage2 written to partition 0, 273 sectors starting at 50 (abs 16115)

10. We can boot from c0d1 and check the status