Manage zpool and zfs in solaris 10

What is ZFS:

ZFS is a new kind of file system that provides simple administration, transactional semantics, end-to-end data integrity, and immense scalability. ZFS is not an incremental improvement to existing technology; it is a fundamentally new approach to data management

ZFS is managed by two commands zpool and zfs

zpool- Manages ZFS pool and devices within them

zfs – Manages zfs filesystem

In this example I will be using filename as disk1, disk2, disk3 and disk4.

1. Create four 128mb files.

# mkfile 128m /export/home/disk1
# mkfile 128m /export/home/disk2
# mkfile 128m /export/home/disk3
# mkfile 128m /export/home/disk4

Pools:

Before creating new pools look for existing pool

#zpool list

no pools available

Create zpool

# zpool create data /export/home/disk1

# zpool list
NAME   SIZE   USED  AVAIL    CAP  HEALTH  ALTROOT
data   123M    75K   123M     0%  ONLINE  –

# df -ah

You can see no volume management,newfs or mount is required in zfs. Now you have working pool with mounted zfs filesystem.

 

A pool with single disk does not offer redundancy. So we will mirror it.

# zpool destroy data

# zpool list

no pools available

Mirror the pool

# zpool create data mirror /export/home/disk1 /export/home/disk2

# zpool list

NAME   SIZE   USED  AVAIL    CAP  HEALTH  ALTROOT
data   123M  76.5K   123M     0%  ONLINE  –

Check the status of zpool

# zpool status data

pool: data
state: ONLINE
scrub: none requested
config:

NAME                               STATE       READ WRITE CKSUM
data                               ONLINE       0        0         0
mirror                           ONLINE       0        0         0
/export/home/disk1     ONLINE       0        0         0
/export/home/disk2     ONLINE       0        0         0

errors: No known data errors

Now we can see that pool conatins mirror of two disks. Now we will create a file to see how use changes

# mkfile 32m /data/foo

# zpool status

NAME   SIZE   USED  AVAIL    CAP  HEALTH  ALTROOT
data   123M  28.7M  94.3M    23%  ONLINE  –

We can detattach the device

# zpool detach data /export/home/disk1

# zpool status

zpool status
pool: data
state: ONLINE
scrub: none requested
config:

NAME                                  STATE     READ WRITE CKSUM
data                                   ONLINE       0     0     0
/export/home/disk2           ONLINE       0     0     0

errors: No known data errors

To attach another disk or same disk

# zpool attach data /export/home/disk2 /export/home/disk1

Adding to a mirror pool:

You can add disk to a pool without taking it offline

# zpool list
NAME   SIZE   USED  AVAIL    CAP  HEALTH  ALTROOT
data   123M  32.2M  90.8M    26%  ONLINE  –

# zpool add data mirror /export/home/disk3 /export/home/disk4

# zpool list
NAME   SIZE   USED  AVAIL    CAP  HEALTH  ALTROOT
data   246M  32.2M   214M    13%  ONLINE  –

# zpool status data
pool: data
state: ONLINE
scrub: resilver completed with 0 errors on Tue Aug 31     13:57:01 2010
config:

NAME                                       STATE     READ WRITE CKSUM
data                                         ONLINE       0     0     0
mirror                                     ONLINE       0     0     0
/export/home/disk2               ONLINE       0     0     0
/export/home/disk1               ONLINE       0     0     0
mirror                                     ONLINE       0     0     0
/export/home/disk3               ONLINE       0     0     0
/export/home/disk4               ONLINE       0     0     0

errors: No known data errors

We can also see currently how much data is written

# zpool iostat -v data
capacity         operations    bandwidth
pool                                 used  avail   read  write   read  write
———————-  —–  —–  —–  —–  —–  —–
data                                32.2M   214M      0      0  26.4K    758
mirror                           32.2M  90.8M      0      1  78.4K  2.13K
/export/home/disk2      –      –               0       2  54.3K  33.7K
/export/home/disk1      –      –      0      3           665  86.3K
mirror                           16K     123M      0      0      0    111
/export/home/disk3      –      –      0      2    522  9.02K
/export/home/disk4      –      –      0      2     92  9.02K
———————-  —–  —–  —–  —–  —–  —-

Now we will create zfs file system

#  zpool list
NAME   SIZE   USED  AVAIL    CAP  HEALTH  ALTROOT
data   246M  32.2M   214M    13%  ONLINE  –

# zfs list
NAME   USED  AVAIL  REFER  MOUNTPOINT
data  32.2M   182M  32.0M  /data

# zfs create data/data1

# zfs create data/data2

# zfs create data/data3

# zfs list
NAME         USED  AVAIL  REFER  MOUNTPOINT
data        32.2M   182M  32.0M  /data
data/data1    21K   182M    21K  /data/data1
data/data2    21K   182M    21K  /data/data2
data/data3    21K   182M    21K  /data/data3

Do df -ah and you will see the zfs file system mount point

# df -ah

We can remove zfs file system by command

# zfs destroy data/data3