New Fusion Drive

[Einsteiniac]

Yet another update.

Alright so my real Mac successfully booted from this setup. Again no clue if 10.8.2 is now moving stuff around to their "ideal" locations or not though as the speeds of the devices I am testing are slow. Anyway the weird thing is if I option boot the Mac to get to the boot loader I will see both the FW and USB devices show up there one with the name Test and the other Test 2. Heading home here in a bit and can test with some real equipment as well as the hack.

 

[Einsteiniac]

Alright another update.

Got home created the LVG with a 250 GB SSD and 2TB HDD. Booted from a normal 10.8.2 installer and installed the OS. It rebooted but I got Chimera from my SSD. It showed the LVG as two separate volumes. I called it Fusion, so it showed Fusion and Fusion 2 in Chimera. Both are green in color. I click on either and it starts to boot! However I always get a KP related to core storage. Now I know for a fact this same process works fine on a real Mac. So not quite sure what is going on. Anyway here is a screen grab of the KP.

 

[Bimbo69]

I think more about fusion drive it seem like one step ahead of concatenated disks.
http://support.apple.com/kb/PH5834
Create a concatenated disk set

Increase storage space with a concatenated RAID set (also called “Just a Bunch of Disks” or JBOD). If you need one large disk, but you have only several smaller disks, you can create a concatenated disk set to use several small disks as one large disk.

1. Open Disk Utility, in the Utilities folder in Launchpad.
2. Select one of the disks that you want in the set, and then click RAID.
3. Click Add (+), and type a name for the RAID set.
4. Choose a format from the Format pop-up menu. Usually you’ll choose the Mac OS Extended (Journaled) format.
5. Choose Concatenated Disk Set from the RAID Type pop-up menu.
6. Drag the disks you want to add to the set to the list on the right.
7. Click Create.

So based on this I wonder if it could be created one of this for example a 128Gb SSD + 1Tb HDD and if it will be recognized as a single drive by chimera/chameleon?
in addition "The version of Disk Utility that comes with Fusion Drive is unique. Earlier versions of Disk Utility can't be used with a Fusion Drive."...maybe it is in new 10.8.2 update for imac/macmini late 2012
to make it finally work dinamically there has to be some app that moves files used to the begining and lees used to the end (or begining after 128gb approx)...So the idea could be "making two drives to work like a fusion drive"...maybe I'm gettin nuts...or not.

 

[Einsteiniac]

Some more testing. Well since I couldn't boot from my setup I decided just to test the performance of my new LVM to see what would happen. I have both these drives plugged into SATAII but both are SATAIII. Anyway writing data to the LVM from my SSD. I was able to get full speed of about 250MB/s until I have about 200GB then the speeds dropped to about 150MB/s which makes sense as now I am writing data to the HDD. So long story I generated data on this drive until I got to 300GB. Then at that point I took a 30GB disk image and duplicated it. It duplicated at the 150MB/s speed. I then copied said disk image off the drive to my SSD and something interesting happened. It copied at ALMOST full speed. It hovered right around 220MB/s. So I am not sure what exactly is going on here as the data was surely 100% stored on the HDD yet my speeds indicate they were coming from the SSD. It however doesn't appear to be offloading data to the HDD. I kept my activity monitor open for a few hours and nothing but normal usage showed there. Also copying more data still happens as the slower speeds. I know my HDD isn't giving that kind of performance as testing with Blackmagic yields 150/150 on the HDD. Either way it was an interesting result. When I get home tonight I will test the speeds again copying data and see if I have different results.

 

[thedrez]

I haven't looked into this very deeply but this fusion drive sounds a lot like the tiered storage capabilities of ZFS. Once upon a time, I remember that there were rumors that OSX would eventually switch to ZFS as a primary filesystem. That rumor died sometime before Oracle acquired Sun. Oracle (I saw the Sun version of the presentation) showed how an enterprise could have SSDs, 15k rpm SAS and 7200 rpm SATA drives in a series of enclosures connected to a Solaris based controller server and the ZFS configuration would put the most frequently used/accessed info on SSDs, then the SAS drives would be the next fastest followed by SATA for the less frequent info. I think they even mentioned that tape libraries could be integrated as well. I didn't follow the tape logic of the discussion because it seemed worthless to buy really expensive LTO tape cartridges when SATA are so cheap.

Just thought I'd share...

 

[gsxr]

you should be able to boot using the uuid thats what i did to boot from raid
have loader on usb stick and set boot to uuid of raid

open disk util to get uuid

 

[adammerkley]

Former Hackintosh user, now a legit Mac Mini user.

Just wanted to say I'm eagerly awaiting you guys figuring out how to enable Fusion Drive on hardware that doesn't officially support it. I'd love to turn my Mac Mini's SSD + HD configuration into a home brewed Fusion Drive.

 

[maclover]

FD not recommendet for avarege user

Former Hackintosh user, now a legit Mac Mini user.

Just wanted to say I'm eagerly awaiting you guys figuring out how to enable Fusion Drive on hardware that doesn't officially support it. I'd love to turn my Mac Mini's SSD + HD configuration into a home brewed Fusion Drive.

I would not encourage or urge normal user to go the fusion route.
It's a transitional technology owed the the lack of big cheap SSD's.

1. It will disapear as soon as cheap big SSD are widely available.
2. FD makes the configuration more complicated (confusing users to configure it similar to NAS using LVM groups) ,
3. it increases the number of single points of failure (integrity of filesystem).
4. It reduces the lifetime of SSD since it frequently copies a large amount of data trough HDD and SSD forth and back depending on users habits (mostly used progs and data).

So I feel no urge to use it on my Hack and iMac too.

 

[nige2000]

was initially interested in this for a hack, but now i realise the life of the fusion software will be short, as ssds will become cheaper and bigger
just too much hassle for me

only use would be with a 8/16gb msata drive on the built in slot on the z77 boards if someone could get it working

 

[minihack]

Einsteiniac, interested in what you are doing here.

Just wondered if you have read this article on undocumented commands in Corestorage and also looking at the recent comments at the end of the article.

I find it intriguing. http://blog.fosketts.net/2011/08/05/undocumented-corestorage-commands/

I am wondering if some of this undocumented stuff mentioned in this very interesting blog is now more functional under the new updates (the author talks of some of the commands not seeming to work) and might underpin the Fusion Drive creation.