ZFS on a USB Disk (removable Media)
With a relatively recent versions of Solaris or OpenSolaris (say Nevada build 36, Solaris Express 4/06 and Solaris 10 6/06 release), here is how it is possible to use ZFS as the backing file system for such a removable device, easily.
The first step is certainly to disable the
service, for the operating system not trying to mount it automatically each
time this device will be plugged in:
# svcadm disable volfs
Knowing that Solaris USB driver presents any USB storage device as removable
media, it can be seen using both the
format command in expert
mode, and the
# format -e < /dev/null Searching for disks...done AVAILABLE DISK SELECTIONS: 0. c1d0 <DEFAULT cyl 9720 alt 2 hd 255 sec 63> /pci@0,0/pci-ide@7/ide@0/cmdk@0,0 1. c2d0 <ST325082- 4ND0XKT-0001-232.89GB> /pci@0,0/pci-ide@7/ide@1/cmdk@0,0 2. c3t0d0 <ST940211-5A-0000-37.26GB> /pci@0,0/pci108e,5347@2,1/storage@3/disk@0,0 Specify disk (enter its number): # # rmformat Looking for devices... 1. Logical Node: /dev/rdsk/c0t0d0p0 Physical Node: /pci@0,0/pci-ide@6/ide@0/sd@0,0 Connected Device: LITE-ON DVD SOHD-16P9S F3S2 Device Type: DVD Reader Bus: IDE Size: <Unknown> Label: <Unknown> Access permissions: <Unknown> 2. Logical Node: /dev/rdsk/c3t0d0p0 Physical Node: /pci@0,0/pci108e,5347@2,1/storage@3/disk@0,0 Connected Device: ST940211 5A 0000 Device Type: Removable Bus: USB Size: 38.2 GB Label: <Unknown> Access permissions: Medium is not write protected.
Now that the device name is clearly identified, it possible to create a
# zpool create rmzp c3t0d0 # zpool list rmzp NAME SIZE USED AVAIL CAP HEALTH ALTROOT rmzp 37G 28.6M 37.0G 0% ONLINE -
Since the purpose of this disk is, among other things, to be a backup of my home directory, here is how to do so.
First, create the correct
zfs hierarchy on the USB disk:
# zfs create rmzp/home # zfs set compression=on rmzp/home
Take a snapshot of current home directory, send and restore it on the fly to
# zfs snapshot email@example.com # zfs send firstname.lastname@example.org | zfs receive rmzp/home/jgabel # zfs destroy email@example.com # zfs list -r rmzp NAME USED AVAIL REFER MOUNTPOINT rmzp 28.6M 36.4G 25.5K /rmzp rmzp/home 28.5M 36.4G 26.5K /rmzp/home rmzp/home/jgabel 28.5M 36.4G 28.5M /rmzp/home/jgabel
Then, when you are ready to take it away, just export the
as with a classical disk:
# zpool export rmzp # zpool list rmzp cannot open 'rmzp': no such pool # zpool import pool: rmzp id: 1670601809438763813 state: ONLINE action: The pool can be imported using its name or numeric identifier. config: rmzp ONLINE c3t0d0 ONLINE
Wow! What an easy and powerful way to do backups on removable media, isn't it?