Thursday June 26, 2008
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Thursday June 26, 2008 ZFS and Mac OS X Time Machine: The Perfect Team
A few months ago, I wrote about "X4500 + Solaris ZFS + iSCSI = Perfect Video Editing Storage". And thanks to you, my readers, it became one of my most popular blog entries. Then I wrote about "VirtualBox and ZFS: The Perfect Team", which turned out to be another very popular blog article. Well, I'm glad to introduce you to another perfect team now: Solaris ZFS and Mac OS X Time Machine.
Actually, it began a long time ago: In December '06, Ben Rockwood wrote about the beauty of ZFS and iSCSI integration, and immediatley I thought "That's the perfect solution to back up my Mac OS X PowerBook!" No more strings attached, just back up over WLAN to a really good storage device that lives on Solaris ZFS, while still using the Mac OS X native file system peculiarities. But Apple didn't have an iSCSI initiator yet (they still don't have one now) and the only free iSCSI initiator I could find was buggy, unstable and didn't like Solaris targets at all.
Then, Apple announced their Time Machine technology. Many people thought that this was related to them supporting ZFS and in fact, it's easy to believe that Time Machine's travels back in time are supported by ZFS snapshots. But they aren't. In reality, it's just a clever use of hardlinks. And not a very efficient one, too: Whenever a file changes, the whole file gets backed up again, even if you just changed a little bit of it.
Last week, a colleague of mine told me that Studio Networks Solutions had updated their globalSAN iSCSI Initiator software for Mac OS X and that it now works well with Solaris iSCSI targets. I decided to give it another try. So, here are two ZFS ZVOLs sitting on my OpenSolaris 2008.05 home server:
Sun Microsystems Inc. SunOS 5.11 snv_86 January 2008
-bash-3.2$ zfs list -rt volume
NAME USED AVAIL REFER MOUNTPOINT
santiago/volumes/aperturevault 6.50G 631G 6.50G -
santiago/volumes/mbptm 193G 631G 193G -
-bash-3.2$
They have both been shared as iSCSI targets through a single zfs set shareiscsi=on santiago/volumes command, thanks to ZFS' attribute inheritance:
-bash-3.2$ zfs get shareiscsi santiago/volumes
NAME PROPERTY VALUE SOURCE
santiago/volumes shareiscsi on local
-bash-3.2$ zfs get shareiscsi santiago/volumes/aperturevault
NAME PROPERTY VALUE SOURCE
santiago/volumes/aperturevault shareiscsi on inherited from santiago/volumes
-bash-3.2$ zfs get shareiscsi santiago/volumes/mbptm
NAME PROPERTY VALUE SOURCE
santiago/volumes/mbptm shareiscsi on inherited from santiago/volumes
-bash-3.2$
On the Mac side, they show up in the globalSAN GUI just nicely:
And Disk Utility can format them perfectly as if they were real disks:
Time Machine happily accepted one of the iSCSI disks and synced more than 190GB to it just fine and as I type these lines, Aperture is busy syncing more than 40GB of photos to the other iSCSI disk (it wouldn't accept a network share). Sometimes, they're busy working simultaneously :).
Of course, iSCSI performance heavily depends on network performance, so for larger transfers, a cable connection is mandatory. But the occasional Time Machine or Aperture sync in the background runs just fine over WLAN.
So finally, Solaris and Mac fans can have a Time Machine based on ZFS, with real data integrity, redundancy, robustness, two different ways of travelling through time (ZVOLs can be snapshotted just like regular ZFS file systems) and much more.
Many thanks to Christiano for letting me know and to the guys at Studio Network Solutions for making this possible. And of course to the ZFS team for a wonderful piece of open storage software!
"ZFS and Mac OS X Time Machine: The Perfect Team" has been brought to you by Constantin's Blooog.
This entry was created on 2008-06-26 14:40:55.0 PST and is associated with the following tags:
backup
globalsan
iscsi
mac
machine
os
storage
time
x
zfs
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