Expanding ZFS rpool in Solaris 10

I was really bad at googling the steps to grow ZFS rpool online without using zpool append, so here is my little story how I’ve done it.
Before I begin, please, note that everything said below applies only to the configurations where rpool consumes a whole disk. If there is another partition sitting right after (or with some gap) your rpool, you’re risking to corrupt the data. So don’t blindly use the last cylinder (or “$”) when it’s time to modify the partition table.

  1. Here is the rpool:
    2. # zpool list rpool
NAME    SIZE  ALLOC   FREE  CAP  HEALTH  ALTROOT
rpool  31.1G  23.6G  7.52G  75%  ONLINE  -
  2. Saving the partition table first so later this information could be used to correctly re-lable (re-partition) the expanded disk. Btw, use “zpool status rpool -v” to find the device name:
    3. # prtvtoc /dev/dsk/c4t60060E80167D3C0000017D3C000010CAd0s2
* /dev/dsk/c4t60060E80167D3C0000017D3C000010CAd0s2 partition map
*
* Dimensions:
*     512 bytes/sector
*     512 sectors/track
*      15 tracks/cylinder
*    7680 sectors/cylinder
*    8533 cylinders
*    8531 accessible cylinders
*
* Flags:
*   1: unmountable
*  10: read-only
*
*                          First     Sector    Last
* Partition  Tag  Flags    Sector     Count    Sector  Mount Directory
       0      2    00          0  65518080  65518079
       2      5    01          0  65518080  65518079
  3. Behind the scene LUN was expanded. To confirm that luxadm could be quite handy (pay attention to “Unformatted capacity”) field:
    4. # luxadm display /dev/rdsk/c4t60060E80167D3C0000017D3C000010CAd0s2
DEVICE PROPERTIES for disk: /dev/rdsk/c4t60060E80167D3C0000017D3C000010CAd0s2
  Vendor:               HITACHI
  Product ID:           OPEN-V      -SUN
  Revision:             7006
  Serial Num:           50 17D3C10CA
  Unformatted capacity: 36864.000 MBytes
  Read Cache:           Enabled
    Minimum prefetch:   0x0
    Maximum prefetch:   0x0
  Device Type:          Disk device
  4. Time for the scariest part, i.e. re-lable the disk by installing a new partition table.
    To be able to do that a new disk’s geometry must be somehow conveyed to the format utility and that’s surprisingly easy to achieve. Just run format, select the disk and use “type” option to autoconfigure it:
    5. # format
Searching for disks...done

AVAILABLE DISK SELECTIONS:
       0. c1t0d0 
          /pci@0/pci@0/pci@2/scsi@0/sd@0,0
       1. c4t60060E80167D3C0000017D3C000010CAd0 
          /scsi_vhci/ssd@g60060e80167d3c0000017d3c000010ca
Specify disk (enter its number): 1
selecting c4t60060E80167D3C0000017D3C000010CAd0
[disk formatted]
/dev/dsk/c4t60060E80167D3C0000017D3C000010CAd0s0 is part of active ZFS pool rpool. Please see zpool(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
        repair     - repair a defective sector
        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
        inquiry    - show vendor, product and revision
        volname    - set 8-character volume name
        !     - execute , then return
        quit
format> type

AVAILABLE DRIVE TYPES:
        0. Auto configure
        1. Quantum ProDrive 80S
        2. Quantum ProDrive 105S
        3. CDC Wren IV 94171-344
        4. SUN0104
        5. SUN0207
        6. SUN0327
        7. SUN0340
        8. SUN0424
        9. SUN0535
        10. SUN0669
        11. SUN1.0G
        12. SUN1.05
        13. SUN1.3G
        14. SUN2.1G
        15. SUN2.9G
        16. Zip 100
        17. Zip 250
        18. Peerless 10GB
        19. HITACHI-OPEN-V-SUN-7005
        20. SUN300G
        21. other
Specify disk type (enter its number)[19]: 0
c4t60060E80167D3C0000017D3C000010CAd0: configured with capacity of 35.99GB

selecting c4t60060E80167D3C0000017D3C000010CAd0
[disk formatted]
  5. Notice that now it’s configured with a new capacity.
  6. Don’t leave the format prompt yet since we are not done. Next step is to carve out the partition table. Remember, that I only had two partitions (0 for root and 2 for backup) and your situation might be completely different, so don’t copy/paste rashly.
  7. Use the numbers from the menu to select the partition you’re willing to modify:
    8. format> partition
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
        quit
partition>
  8. For me, it was enough to set the size of all partitions to zero except the two: 0 (tagged as root) and 2 (tagged as backup). As you can see below wm (write-mountable) flag was set only for partition 0, whilst the rest have wu (write-unmountable):
    9. partition> print
Current partition table (unnamed):
Total disk cylinders available: 9828 + 2 (reserved cylinders)

Part      Tag    Flag     Cylinders        Size            Blocks
  0       root    wm       0 - 9827       35.99GB    (9828/0/0) 75479040
  1 unassigned    wu       0               0         (0/0/0)           0
  2     backup    wu       0 - 9827       35.99GB    (9828/0/0) 75479040
  3 unassigned    wu       0               0         (0/0/0)           0
  4 unassigned    wu       0               0         (0/0/0)           0
  5 unassigned    wu       0               0         (0/0/0)           0
  6 unassigned    wu       0               0         (0/0/0)           0
  7 unassigned    wu       0               0         (0/0/0)           0
  9. Label the disk and quit the format tool:

    10. partition> label
    Ready to label disk, continue? yes
    partition> q
    format> q

  10. Finally it’s time to grow ZFS rpool and to confirm we’re golden:
    11. # zpool online -e rpool /dev/dsk/c4t60060E80167D3C0000017D3C000010CAd0s0
# zpool list rpool
NAME    SIZE  ALLOC   FREE  CAP  HEALTH  ALTROOT
rpool  35.9G  23.6G  12.3G  65%  ONLINE  -

Good luck and safe expanding your pools.

Posted on November 28, 2015 at 10:02 pm by sergeyt · Permalink
In: SAN, Solaris, ZFS

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