Preface
This is the content from the
Oracle Openworld 2012 ZFS lab.
It was well attended - the feedback was that
it was a little short - thats probably because in writing
it I bacame very time-concious after the ASM/ACFS on Solaris extravaganza I ran last year which was almost too long for mortal man to finish in the 1 hour session. Enjoy.
Table of Contents
Exercise Z.1: ZFS Pools
Exercise Z.2: ZFS File Systems
Exercise Z.3: ZFS Compression
Exercise Z.4: ZFS Deduplication
Exercise Z.5: ZFS Encryption
Exercise Z.6: Solaris 11 Shadow Migration
Introduction
This set of exercises is designed to briefly demonstrate new features in Solaris 11 ZFS file system: Deduplication, Encryption and Shadow Migration. Also included is the creation of zpools and zfs file systems - the basic building blocks of the technology, and also Compression which is the compliment of Deduplication. The exercises are just introductions - you are referred to the ZFS Adminstration Manual for further information. From Solaris 11 onward the online manual pages consist of zpool(1M) and zfs(1M) with further feature-specific information in zfs_allow(1M), zfs_encrypt(1M) and zfs_share(1M). The lab is easily carried out in a VirtualBox running Solaris 11 with 6 virtual 3 Gb disks to play with.
Exercise Z.1: ZFS Pools
Task: You have several disks to use for your new file system. Create a new zpool and a file system within
it.
Lab: You will check the status of existing zpools, create your own pool and expand
it.
Your Solaris 11 installation already has a root ZFS pool.
It contains the root file system. Check this:
root@solaris:~# zpool list
NAME SIZE ALLOC FREE CAP DEDUP HEALTH ALTROOT
rpool 15.9G 6.62G 9.25G 41% 1.00x ONLINE -
root@solaris:~# zpool status
pool: rpool
state: ONLINE
scan: none requested
config:
NAME STATE READ WRITE CKSUM
rpool ONLINE 0 0 0
c3t0d0s0 ONLINE 0 0 0
errors: No known data errors
Note the disk device the root pool is on - c3t0d0s0
Now you will create your own ZFS pool. First you will check what disks are available:
root@solaris:~# echo | format
Searching for disks...done
AVAILABLE DISK SELECTIONS:
0. c3t0d0 <ATA-VBOX HARDDISK-1.0 cyl 2085 alt 2 hd 255 sec 63>
/pci@0,0/pci8086,2829@d/disk@0,0
1. c3t2d0 <ATA-VBOX HARDDISK-1.0 cyl 1534 alt 2 hd 128 sec 32>
/pci@0,0/pci8086,2829@d/disk@2,0
2. c3t3d0 <ATA-VBOX HARDDISK-1.0 cyl 1534 alt 2 hd 128 sec 32>
/pci@0,0/pci8086,2829@d/disk@3,0
3. c3t4d0 <ATA-VBOX HARDDISK-1.0 cyl 1534 alt 2 hd 128 sec 32>
/pci@0,0/pci8086,2829@d/disk@4,0
4. c3t5d0 <ATA-VBOX HARDDISK-1.0 cyl 1534 alt 2 hd 128 sec 32>
/pci@0,0/pci8086,2829@d/disk@5,0
5. c3t6d0 <ATA-VBOX HARDDISK-1.0 cyl 1534 alt 2 hd 128 sec 32>
/pci@0,0/pci8086,2829@d/disk@6,0
6. c3t7d0 <ATA-VBOX HARDDISK-1.0 cyl 1534 alt 2 hd 128 sec 32>
/pci@0,0/pci8086,2829@d/disk@7,0
Specify disk (enter its number): Specify disk (enter its number):
The root disk is numbered 0. The others are free for use. Try creating a simple pool and observe the error message:
root@solaris:~# zpool create mypool c3t2d0 c3t3d0
'mypool' successfully created, but with no redundancy; failure of one
device will cause loss of the pool
So destroy that pool and create a mirrored pool instead:
root@solaris:~# zpool destroy mypool
root@solaris:~# zpool create mypool mirror c3t2d0 c3t3d0
root@solaris:~# zpool status mypool
pool: mypool
state: ONLINE
scan: none requested
config:
NAME STATE READ WRITE CKSUM
mypool ONLINE 0 0 0
mirror-0 ONLINE 0 0 0
c3t2d0 ONLINE 0 0 0
c3t3d0 ONLINE 0 0 0
errors: No known data errors
Back to topExercise Z.2: ZFS File Systems
Task: You have to create file systems for later exercises.
You can see that when a pool is created, a file system of the same name is created:
root@solaris:~# zfs list
NAME USED AVAIL REFER MOUNTPOINT
mypool 86.5K 2.94G 31K /mypool
Create your filesystems and mountpoints as follows:
root@solaris:~# zfs create -o mountpoint=/data1 mypool/mydata1
The -o option sets the mount point and automatically creates the necessary directory.
root@solaris:~# zfs list mypool/mydata1
NAME USED AVAIL REFER MOUNTPOINT
mypool/mydata1 31K 2.94G 31K /data1
Back to top
Exercise Z.3: ZFS Compression
Task:Try out different forms of compression available in ZFS
Lab:Create 2nd filesystem with compression, fill both file systems with the same data, observe results
You can see from the zfs(1) manual page that there are several types of compression available to you, set with the property=value syntax:
compression=on | off | lzjb | gzip | gzip-N | zle
Controls the compression algorithm used for this
dataset. The lzjb compression algorithm is optimized for
performance while providing decent data compression.
Setting compression to on uses the lzjb compression
algorithm. The gzip compression algorithm uses the same
compression as the gzip(1) command. You can specify the
gzip level by using the value gzip-N where N is an
integer from 1 (fastest) to 9 (best compression ratio).
Currently, gzip is equivalent to gzip-6 (which is also
the default for gzip(1)).
Create a second filesystem with compression turned on. Note how you set and get your values separately:
root@solaris:~# zfs create -o mountpoint=/data2 mypool/mydata2
root@solaris:~# zfs set compression=gzip-9 mypool/mydata2
root@solaris:~# zfs get compression mypool/mydata1
NAME PROPERTY VALUE SOURCE
mypool/mydata1 compression off default
root@solaris:~# zfs get compression mypool/mydata2
NAME PROPERTY VALUE SOURCE
mypool/mydata2 compression gzip-9 local
Now you can copy the contents of /usr/lib into both your normal and compressing filesystem and observe the results. Don't forget the dot or period (".") in the find(1) command below:
root@solaris:~# cd /usr/lib
root@solaris:/usr/lib# find . -print | cpio -pdv /data1
root@solaris:/usr/lib# find . -print | cpio -pdv /data2
The copy into the compressing file system takes longer - as
it has to perform the compression but the results show the effect:
root@solaris:/usr/lib# zfs list
NAME USED AVAIL REFER MOUNTPOINT
mypool 1.35G 1.59G 31K /mypool
mypool/mydata1 1.01G 1.59G 1.01G /data1
mypool/mydata2 341M 1.59G 341M /data2
Note that the available space in the pool is shared amongst the file systems. This behavior can be modified using quotas and reservations which are not covered in this lab but are covered extensively in the ZFS Administrators Guide.
Back to top
Exercise Z.4: ZFS Deduplication
The deduplication property is used to remove redundant data from a ZFS file system. With the property enabled duplicate data blocks are removed synchronously. The result is that only unique data is stored and common componenents are shared.
Task:See how to implement deduplication and its effects
Lab: You will create a ZFS file system with deduplication turned on and see if
it reduces the amount of physical storage needed when we again fill
it with a copy of /usr/lib.
root@solaris:/usr/lib# zfs destroy mypool/mydata2
root@solaris:/usr/lib# zfs set dedup=on mypool/mydata1
root@solaris:/usr/lib# rm -rf /data1/*
root@solaris:/usr/lib# mkdir /data1/2nd-copy
root@solaris:/usr/lib# zfs list
NAME USED AVAIL REFER MOUNTPOINT
mypool 1.02M 2.94G 31K /mypool
mypool/mydata1 43K 2.94G 43K /data1
root@solaris:/usr/lib# find . -print | cpio -pd /data1
2142768 blocks
root@solaris:/usr/lib# zfs list
NAME USED AVAIL REFER MOUNTPOINT
mypool 1.02G 1.99G 31K /mypool
mypool/mydata1 1.01G 1.99G 1.01G /data1
root@solaris:/usr/lib# find . -print | cpio -pd /data1/2nd-copy
2142768 blocks
root@solaris:/usr/lib#zfs list
NAME USED AVAIL REFER MOUNTPOINT
mypool 1.99G 1.96G 31K /mypool
mypool/mydata1 1.98G 1.96G 1.98G /data1
You could go on creating copies for quite a while...but you get the idea. Note that deduplication and compression can be combined: the compression acts on metadata.
Deduplication works across file systems in a pool and there is a zpool-wide property dedupratio:
root@solaris:/usr/lib# zpool get dedupratio mypool
NAME PROPERTY VALUE SOURCE
mypool dedupratio 4.30x -
Deduplication can also be checked using "zpool list":
root@solaris:/usr/lib# zpool list
NAME SIZE ALLOC FREE CAP DEDUP HEALTH ALTROOT
mypool 2.98G 1001M 2.01G 32% 4.30x ONLINE -
rpool 15.9G 6.66G 9.21G 41% 1.00x ONLINE -
Before moving on to the next topic, destroy that dataset and free up some space:
root@solaris:~# zfs destroy mypool/mydata1
Back to top
Exercise Z.5: ZFS Encryption
Task: Encrypt sensitive data.
Lab: Explore basic ZFS encryption.
This lab only covers the basics of ZFS Encryption. In particular
it does not cover various aspects of key management. Please see the ZFS Adminastrion Manual and the zfs_encrypt(1M) manual page for more detail on this functionality.
Back to top
root@solaris:~# zfs create -o encryption=on mypool/data2
Enter passphrase for 'mypool/data2': ********
Enter again: ********
root@solaris:~#
Creation of a descendent dataset shows that encryption is inherited from the parent:
root@solaris:~# zfs create mypool/data2/data3
root@solaris:~# zfs get -r encryption,keysource,keystatus,checksum mypool/data2
NAME PROPERTY VALUE SOURCE
mypool/data2 encryption on local
mypool/data2 keysource passphrase,prompt local
mypool/data2 keystatus available -
mypool/data2 checksum sha256-mac local
mypool/data2/data3 encryption on inherited from mypool/data2
mypool/data2/data3 keysource passphrase,prompt inherited from mypool/data2
mypool/data2/data3 keystatus available -
mypool/data2/data3 checksum sha256-mac inherited from mypool/data2
You will find the online manual page zfs_encrypt(1M) contains examples. In particular, if time permits during this lab session you may wish to explore the changing of a key using "zfs key -c mypool/data2".
Exercise Z.6: Shadow Migration
Shadow Migration allows you to migrate data from an old file system to a new file system while simultaneously allowing access and modification to the new file system during the process. You can use Shadow Migration to migrate a local or remote UFS or ZFS file system to a local file system.
Task: You wish to migrate data from one file system (UFS, ZFS, VxFS) to ZFS while mainaining access to
it.
Lab: Create the infrastructure for shadow migration and transfer one file system into another.
First create the file system you want to migrate
root@solaris:~# zpool create oldstuff c3t4d0
root@solaris:~# zfs create oldstuff/forgotten
Then populate
it with some files:
root@solaris:~# cd /var/adm
root@solaris:/var/adm# find . -print | cpio -pdv /oldstuff/forgotten
You need the shadow-migration package installed:
root@solaris:~# pkg install shadow-migration
Packages to install: 1
Create boot environment: No
Create backup boot environment: No
Services to change: 1
DOWNLOAD PKGS FILES XFER (MB)
Completed 1/1 14/14 0.2/0.2
PHASE ACTIONS
Install Phase 39/39
PHASE ITEMS
Package State Update Phase 1/1
Image State Update Phase 2/2
You then enable the shadowd service:
root@solaris:~# svcadm enable shadowd
root@solaris:~# svcs shadowd
STATE STIME FMRI
online 7:16:09 svc:/system/filesystem/shadowd:default
Set the filesystem to be migrated to read-only
root@solaris:~# zfs set readonly=on oldstuff/forgotten
Create a new zfs file system with the shadow property set to the file system to be migrated:
root@solaris:~# zfs create -o shadow=file:///oldstuff/forgotten mypool/remembered
Use the shadowstat(1M) command to see the progress of the migration:
root@solaris:~# shadowstat
EST
BYTES BYTES ELAPSED
DATASET XFRD LEFT ERRORS TIME
mypool/remembered 92.5M - - 00:00:59
mypool/remembered 99.1M 302M - 00:01:09
mypool/remembered 109M 260M - 00:01:19
mypool/remembered 133M 304M - 00:01:29
mypool/remembered 149M 339M - 00:01:39
mypool/remembered 156M 86.4M - 00:01:49
mypool/remembered 156M 8E 29 (completed)
Note that if you had created /mypool/remembered as encrypted, this would be the preferred method of encrypting existing data. Similarly for compressing or deduplicating existing data.
The procedure for migrating a file system over NFS is similar - see the ZFS Administration manual.
That concludes this lab session.
