I recently had the requirement to rename a zfs pool. The normally useful documentation was in this case not very useful Never mind, simple answer. To rename a zfs pool from poola to poolb:

anouk:/ # zpool export poola

anouk:/ # zpool import poola poolb

And you’re done. There really isn’t a simpler or better file system than zfs.

All credit for this one goes to http://www.tech-recipes.com/rx/2787/solaris_delete_zfs_slices_from_a_disk, i just wanted to post it here so i can find it easy next time.

amstel:/ # format -e c4t4d0
selecting c4t4d0
[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
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
inquiry - show vendor, product and revision
scsi - independent SCSI mode selects
cache - enable, disable or query SCSI disk cache
volname - set 8-character volume name
!<cmd> - execute <cmd>, then return
quit
format> l
[0] SMI Label
[1] EFI Label
Specify Label type[1]: 0
Warning: This disk has an EFI label. Changing to SMI label will erase all
current partitions.
Continue? y
Auto configuration via format.dat[no]? y

Now i can use prtvtoc to lay out an empty partition table to the disks.

amstel:/ # prtvtoc /dev/dsk/c4t5d0s2 | fmthard -s - /dev/rdsk/c4t2d0s2
fmthard:  New volume table of contents now in place.

Time to get some backups going of the zfs file systems.

anouk:/work/scripts # zfs list
NAME             USED  AVAIL  REFER  MOUNTPOINT
storage         23.0G  43.4G  31.5K  /storage
storage/backup  1.32G  43.4G  1.32G  /storage/backup
storage/crash   24.5K  43.4G  24.5K  /storage/crash
storage/mp3     14.2G  43.4G  14.2G  /storage/mp3
storage/stuff   7.47G  43.4G  7.47G  /storage/stuff
storage/zones   24.5K  43.4G  24.5K  /storage/zones

Let’s start with the /storage/backup file system.

anouk:/work/scripts # zfs snapshot storage/backup@080118
anouk:/work/scripts # zfs list
NAME                    USED  AVAIL  REFER  MOUNTPOINT
storage                23.0G  43.4G  31.5K  /storage
storage/backup         1.32G  43.4G  1.32G  /storage/backup
storage/backup@080118      0      -  1.32G  -
storage/crash          24.5K  43.4G  24.5K  /storage/crash
storage/mp3            14.2G  43.4G  14.2G  /storage/mp3
storage/stuff          7.47G  43.4G  7.47G  /storage/stuff
storage/zones          24.5K  43.4G  24.5K  /storage/zones
temp                   23.0G  10.2G  23.0G  /temp

It’s that easy.  Any changes will be tracked to the snapshot so i can restore it to this point at any time i choose.

Now to send it to another system for redundancy:

anouk:/storage # zfs send storage/backup@080118 | ssh augustus zfs recv backup/anouk-backup

For the above command to work on the system augustus the zpool backup has to exist but the file system i am sending the snapshot to may not exist.

There, all done.  I have a backup of the file system anouk:/storage/backup at augustus:/backup/anouk-backup

augustus:/backup # zfs list
NAME                         USED  AVAIL  REFER  MOUNTPOINT
backup                      1.32G  6.24G  26.5K  /backup
backup/anouk-backup         1.32G  6.24G  1.32G  /backup/anouk-backup
backup/anouk-backup@080118      0      -  1.32G  -

Consult the zfs administration guide for more info on cloning snapshots as well.

I had corruption in my huge zfs pool last week. After many hours troubleshooting i came to the conclusion it was corrupted beyond repair and i destroyed the pool and started again. I won’t go into the detail here of what happened, but it would appear to be related to the manner in which i connect and disconnect the d1000.

I spoke to a friend of mine who is a hardware expert, and this is what he told me about hot plugging the d1000.

“The scsi-connector of the cable is not hot-plug capable. Period. First requirement would be that during nsertion:
1) ground is established
2) power is enabled, and circuitry is initialised.
3) data lines are connected.

Since the pins of the scsi cable connector are all equal in length, there is no way that the above can happen in the correct sequence.

Look at the connector of the scsi-drive itself. You’ll see pins protruding of different lengths. That’s why the drives in the d1000 are hotpluggable, but the chassis/cable isn’t.

You run the risk of frying the logic on either the HBA or the D1000. If you want to do this sensibly, you poweroff the box and the D1000. Then either connect or disconnect the cable. We’ve seen plenty of HBA’s fried because they were plugged not according to spec. Especially the qus-driver ones). Fair enough, the old PCI-dual channel wide scsi-2 adapters are pretty resilient from what we’ve seen, but then again they weren’t maltreated every week like this.”

So, this morning i was staring at this:

anouk:/ # zpool list
NAME SIZE USED AVAIL CAP HEALTH ALTROOT
storage 136G 71.4G 64.6G 52% ONLINE -
anouk:/ # zpool export storage

The system went into immediate panic.

So after the system finished rebooting started troubleshooting.

anouk:/ # mount -F zfs storage /storage/
cannot open ’storage’: I/O error

anouk:/ # zpool list
NAME SIZE USED AVAIL CAP HEALTH ALTROOT
storage - - - - FAULTED -

anouk:/ # zpool status -x
pool: storage
state: UNAVAIL
status: One or more devices could not be opened. There are insufficient
replicas for the pool to continue functioning.
action: Attach the missing device and online it using ‘zpool online’.
see: http://www.sun.com/msg/ZFS-8000-D3
scrub: none requested
config:

NAME STATE READ WRITE CKSUM
storage UNAVAIL 0 0 0 insufficient replicas
c1t0d0 UNAVAIL 0 0 0 cannot open

Whilst the disk was there, i could see it touch it and play with it.

anouk:/ # format
… <snip>
Specify disk (enter its number): 2
selecting c1t0d0
[disk formatted]
/dev/dsk/c1t0d0s0 is part of active ZFS pool storage. Please see zpool(1M).

anouk:/ # zpool online storage c1t0d0
cannot open ’storage’: pool is unavailable

anouk:/ # zpool status -v storage
pool: storage
state: UNAVAIL
status: One or more devices could not be opened. There are insufficient
replicas for the pool to continue functioning.
action: Attach the missing device and online it using ‘zpool online’.
see: http://www.sun.com/msg/ZFS-8000-D3
scrub: none requested
config:

NAME STATE READ WRITE CKSUM
storage UNAVAIL 0 0 0 insufficient replicas
c1t0d0 UNAVAIL 0 0 0 cannot open

Tried rebooting, to no avail. Solaris could see the disk but zfs could not. From my zfs troubleshooting a few days earlier i remember the zpool.cache file in /etc/zfs.

anouk:/ # ls -la /etc/zfs
total 14
drwxr-xr-x 2 root sys 512 Dec 26 23:28 .
drwxr-xr-x 82 root sys 4608 Dec 28 09:34 ..
-rw-r–r– 1 root root 852 Dec 26 23:28 zpool.cache

anouk:/ # rm /etc/zfs/zpool.cache
anouk:/ # init 6

anouk:/ # zpool status -x
no pools available
anouk:/ # zpool list
no pools available
anouk:/ # zpool import
pool: storage
id: 10619813594259770929
state: ONLINE
action: The pool can be imported using its name or numeric identifier.
config:

storage ONLINE
c1t0d0 ONLINE

anouk:/ # zpool import storage
cannot import ’storage’: pool may be in use from other system
use ‘-f’ to import anyway
anouk:/ # zpool import -f storage
anouk:/ # zpool status -v pool: storage
state: ONLINE
scrub: none requested
config:

NAME STATE READ WRITE CKSUM
storage ONLINE 0 0 0
c1t0d0 ONLINE 0 0 0

errors: No known data errors
anouk:/ # mount -F zfs storage /storage/
anouk:/ # df -k
… <snip>
storage 140378112 74860993 65516734 54% /storage

And all is well again. With all the zfs problem in the last week i think i will listen to the scsi expert and not hotplug the d1000 again. Fortunately the lost data is a backup of data which has not been lost.