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ZFS – How to increase rpool in Solaris

We have an issue in ZFS “the next generation filesystem”  as well.In ZFS, you can not extend the root pool by adding new disks.But it has some logic too. For an example,if you are having more than one harddisk in root zpool, loss of one disk result be un-bootable system.To eliminate these kind of situations ,its better to keep the rpool in one disk and mirror it instead of spreading over the multiple disks.

But sometimes project team will commit mistake by keeping /var, /usr, /home under rpool and system may running out of root disk space.
EFI labels are not supported for Solaris rpool. rpool disk must be SMI labeled and all the sectors to be set on partition 0 like the below one.
Part      Tag    Flag     First Sector       Size       Last Sector
0 usr wm 256 1015.86MB 2080733
1 unassigned wm 0 0 0
2 unassigned wm 0 0 0
3 unassigned wm 0 0 0
4 unassigned wm 0 0 0
5 unassigned wm 0 0 0
6 unassigned wm 0 0 0
8 reserved wm 2080734 8.00MB 2097117

For a test,Here i am trying to extend the rpool using new disk,

# zpool add rpool c1t8d0s0
cannot add to 'rpool': root pool can not have multiple vdevs or separate logs


Solution:
There is only one way to extend the rpool space.Please see the below steps:
1.Add a bigger size root hard disk.(i.e If current root disk is 40GB,then add 80GB harddisk)
2.Mirror the rpool using the new 80GB harddsik
3.Installboot block in new disk
4.Detach the old disk from rpool

My setup:

# zpool list rpool
NAME SIZE ALLOC FREE CAP HEALTH ALTROOT
rpool 11.9G 8.56G 3.38G 71% ONLINE -
# zpool status rpool
pool: rpool
state: ONLINE
scrub: none requested
config:
NAME STATE READ WRITE CKSUM
rpool ONLINE 0 0 0
c1t0d0s0 ONLINE 0 0 0
errors: No known data errors


Here i am going to extend my rpool to 20GB. My new 20GB hardisk is c1t9d0.

# format c1t9d0
selecting c1t9d0
[disk formatted]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
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> p
WARNING - This disk may be in use by an application that has
modified the fdisk table. Ensure that this disk is
not currently in use before proceeding to use fdisk.
format> fdisk
No fdisk table exists. The default partition for the disk is:
a 100% "SOLARIS System" partition
Type "y" to accept the default partition, otherwise type "n" to edit the
partition table.
y
format> 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
! - execute , then return
quit
partition>
partition> 0
Part Tag Flag Cylinders Size Blocks
0 unassigned wm 0 0 (0/0/0) 0

Enter partition id tag[unassigned]:
Enter partition permission flags[wm]:
Enter new starting cyl[0]:1
Enter partition size[0b, 0c, 0e, 0.00mb, 0.00gb]: 2606c
partition> p
Current partition table (unnamed):
Total disk cylinders available: 2607 + 2 (reserved cylinders)

Part Tag Flag Cylinders Size Blocks
0 unassigned wm 1 - 2605 19.96GB (2606/0/0) 41865390
1 unassigned wm 0 0 (0/0/0) 0
2 backup wu 0 - 2606 19.97GB (2607/0/0) 41881455
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 unassigned wm 0 0 (0/0/0) 0
partition> l
Ready to label disk, continue? y
partition> q
format> q
#



Now we are going to mirror the rpool with new disk.

# zpool attach rpool c1t0d0s0 c1t9d0s0
Please be sure to invoke installgrub(1M) to make 'c1t9d0s0' bootable.
Make sure to wait until resilver is done before rebooting.
bash-3.00# zpool status rpool
pool: rpool
state: ONLINE
status: One or more devices is currently being resilvered. The pool will
continue to function, possibly in a degraded state.
action: Wait for the resilver to complete.
scrub: resilver in progress for 0h0m, 0.08% done, 7h6m to go
config:
NAME STATE READ WRITE CKSUM
rpool ONLINE 0 0 0
mirror-0 ONLINE 0 0 0
c1t0d0s0 ONLINE 0 0 0
c1t9d0s0 ONLINE 0 0 0 6.82M resilvered
errors: No known data errors


Once the mirroring is done ,we are good to detach the old disk from zpool.But make sure you have made the new disk bootable by updating bootblock.
bash-3.00# zpool detach rpool c1t0d0s0
bash-3.00# zpool status rpool
pool: rpool
state: ONLINE
scrub: resilver completed after 0h31m with 0 errors on Tue May 7 02:05:56 2013
config:

NAME STATE READ WRITE CKSUM
rpool ONLINE 0 0 0
c1t9d0s0 ONLINE 0 0 0 8.56G resilvered

errors: No known data errors
bash-3.00# df -h /
Filesystem size used avail capacity Mounted on
rpool/ROOT/rpooldataset
12G 5.6G 1.6G 78% /
bash-3.00# installgrub /boot/grub/stage1 /boot/grub/stage2 /dev/rdsk/c1t9d0s0
stage1 written to partition 0 sector 0 (abs 16065)
stage2 written to partition 0, 273 sectors starting at 50 (abs 16115)


Installgrub will work only on X86 servers. For SPARC serves,please use installboot.

# installboot -F zfs /usr/platform/`uname -i`/lib/fs/zfs/bootblk /dev/rdsk/c1t9d0s0

You may wondering after doing all the stuff’s root disk space is not increased ? You have to do one small thing to activate the trick. Perform the scrub on rpool and set autoexpand to get the new size.

# zpool scrub rpool
# zpool status rpool
pool: rpool
state: ONLINE
scrub: scrub in progress for 0h9m, 70.77% done, 0h4m to go
config:
NAME STATE READ WRITE CKSUM
rpool ONLINE 0 0 0
c1t9d0s0 ONLINE 0 0 0

# zpool status rpool
pool: rpool
state: ONLINE
scrub: scrub completed after 0h19m with 0 errors on Tue May 7 02:36:21 2013
config:
NAME STATE READ WRITE CKSUM
rpool ONLINE 0 0 0
c1t9d0s0 ONLINE 0 0 0

errors: No known data errors
bash-3.00# df -h /
Filesystem size used avail capacity Mounted on
rpool/ROOT/rpooldataset
12G 5.6G 1.6G 78% /
bash-3.00# zpool set autoexpand=on rpool
bash-3.00# df -h /
Filesystem size used avail capacity Mounted on
rpool/ROOT/rpooldataset
20G 5.6G 9.5G 38% /

Now you can see root filesystem has been extended to 20GB. 

Thank you for reading this article. Please leave a comment if you have any doubt .I will get back to you .

VMTURBO-CLOUD-CAPACITY

7 comments

  1. Ramprasad Karri

    Hi mate just now i tried to increase the rpool i have done every thing as per the procedure but after rebooting the box its not comming up, my box is X86

    • Have you ran installgrub command prior to reboot the system ? what error you are getting when you boot the system ? have you tried to boot from the DVD and tried to install the boot block ?

      Regards
      Lingeswaran

  2. installgrub is no longer the way to install a boot block on x86. New command is bootadm.
    ie., bootadm install-bootloader -P rpool

  3. Nicely written except for the installgrub and bootadm which has no comment.

  4. I tried this on one of our Solaris 10 servers (SunOS name 5.10 Generic_142909-17 sun4u sparc SUNW,Sun-Fire-V490) and it doesn’t work. I followed the steps above, and ‘zpool list’ shows the same size (2 TB) before and after, whereas luxadm display now shows
    # luxadm display /dev/rdsk/c4t600507640081017A080000000000004Dd0s2
    DEVICE PROPERTIES for disk: /dev/rdsk/c4t600507640081017A080000000000004Dd0s2
    Vendor: IBM
    Product ID: 2145
    Revision: 0000
    Serial Num: 010020405e82XX00
    Unformatted capacity: 3145728.000 MBytes
    Read Cache: Enabled
    Minimum prefetch: 0x0
    Maximum prefetch: 0x0
    Device Type: Disk device
    Path(s):

    /dev/rdsk/c4t600507640081017A080000000000004Dd0s2
    /devices/scsi_vhci/ssd@g600507640081017a080000000000004d:c,raw

    Does autoexpand not work for our old version of Solaris? Or is there something else I can try?

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