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Fusion SSD very slow with Mavericks

I think Apple has done something to avoid homemade fusion drives in Mavericks.
I have rolled back to ML and it's fine again.
Mavericks doesn't like DIY Fusion drives, specially with external TB SSD.
I hope it's just a bug that will be fixed in future versions ...
 
After checking with ML, I also have bad write performance with my homemade FD.
I have rolled back to the standard setup with internal HD only.
Then I have tried to check my empty Lacie SSD with blackmagic and I have very bad write perfs !!!
Something is broken with my SSD, I don't know how to fix it ...
 
First off your problem may not be the same as mine so this may not help, secondly if you do try any of this don't just blindly enter the commands into Terminal. You need to make sure you are using the correct disk e.g. disk0, disk1, disk2 as they may be different on your computer.


So I've fixed my DIY Fusion Drive, though it took a while to figure it out as:

a) After upgrading to Mavericks from Mountain Lion the Fusion Drive was working the wrong way. It was attempting to place everything that was accessed the most frequently on the HDD and then placing the least accessed data on the SSD.

b) I wiped all my internal drives (zeroed out the first part of them using dd) so there was no remnants of the old Fusion Drive. I used an install of Mavericks running off a usb drive to create a new Fusion Drive with the following commands:-

Code: 
diskutil cs create "Macintosh HD" disk0 disk1
Code: 
diskutil coreStorage createVolume ########-#######-####### jhfs+ "Macintosh HD" 100%

This resulted in a Fusion Drive with a Recovery HD partition on disk0 (SSD) and a Boot OS X partition on disk1 (HDD).

Everything looked fine so I installed OSX using the .app from inside the Mavericks install running off the USB drive. The installation took a long time, once booted into the fresh install it was quite slow. To try to see what was happening I used:

Code: 
iostat disk0 disk1 1

To show which drive was in use when reading and writing data, while that command was running I used:

Code: 
mkfile 1000m test

Which created a large file, so I could watch to see what was happening with the two drives. The result was that all the writes were happening on the HDD. Additionally when launching programs only the HDD was being used.

c) I wiped the two drives once again and attempted to create another Fusion Drive as I wanted to see whether it was a problem before or after installing an OS onto it. The result was that a clean Fusion Drive exhibited the same problem where all the reads and writes were first going to the HDD.

The instructions below are the ones which made it work correctly for me.
d) I decided to try and mirror the exact setup of Apples Fusion Drive. It appeared that using a running copy of Mavericks was not going to work so I created a bootable memory stick with:

Code: 
sudo /Applications/Install\ OS\ X\ Mavericks.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ OS\ X\ Mavericks.app --nointeraction

I then performed the following steps:-
1) Booted off the USB installer, and wiped both drives by running the following commands for a few seconds:

Code: 
dd if=/dev/zero of=/dev/rdisk0 bs=1m
Code: 
dd if=/dev/zero of=/dev/rdisk1 bs=1m

2) I used Disk Utility to create a partition on the HDD.

3) I installed Mavericks onto this partition. (This was to get the recovery partition onto the HDD as I didn't trust the existing ones I had, so i didn't want to just clone an existing one)

4) I then booted back off the usb installer once again, then ran the following commands to create the fusion drive:

Code: 
diskutil cs create "Macintosh HD" disk0 disk1s2

Where disk1s2 is the partition containing the install of OSX which was completed in step 3.
Suspiciously this only took a few seconds, versus when I tried setting it up on previous attempts where it would take several minutes.

5) Next I formatted the Fusion Drive:

Code: 
diskutil cs createVolume ########-#######-####### jhfs+ "Macintosh HD" 100%

Where the # is the UUID which is given by the previous step.
This creates a Fusion Drive but leaves the Recovery HD on the HDD and places the smaller Boot OS X parition on the SSD.

6) I once again ran the OS X installer (on the USB installer) to install OS X onto the Fusion Drives "Macintosh HD" partition.

After install I tested the Fusion Drive once more, this time it appeared to function correctly and the computers performance felt a lot closer to that of the Fusion Drive under Mountain Lion, with the write speeds back up to where I would expect it to be.


I used both pintofcode.com and jollyjinx.tumblr.com for details on settig up and testing the Fusion Drive. I also used Arstechnica for the information on how a non-DIY Fusion Drive is setup.
 
Dark Dragoon said:
So I've fixed my DIY Fusion Drive, though it took a while to figure it out as:
Click to expand...

So, it seems that it matters which drive either your boot partition or recovery partition lives on. Is this the only difference between your working and non-working setups?
 
satcomer said:
Dark Dragon do you have the Recovery partition still?
Click to expand...

Yes.

You can see the partitions I have below, where disk0 is my SSD (HDD bay) and disk1 is my HDD (Optical bay).
Code: 
/dev/disk0
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *512.1 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:          Apple_CoreStorage                         511.8 GB   disk0s2
   3:                 Apple_Boot Boot OS X               134.2 MB   disk0s3
/dev/disk1
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk1
   1:                        EFI EFI                     209.7 MB   disk1s1
   2:          Apple_CoreStorage                         999.3 GB   disk1s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk1s3
/dev/disk2
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS Macintosh HD           *1.5 TB     disk2


matamoris said:
So, it seems that it matters which drive either your boot partition or recovery partition lives on. Is this the only difference between your working and non-working setups?
Click to expand...
It's the only visible difference, though I'm hessitant to say whether this is the actual cause or not. Especially as creating the Fusion Drive from disk0 and disk1s2 was so much quicker than creating it using disk0 and disk1, so there may be more to it than just the location of the Boot OS X and Recovery HD partitions.


As a side note, I ran the tests without FileVault2. But I have enabled it afterwards and rechecked the setup to make sure that the Fusion Drive is still working fine. Which it is.
 
satcomer said:
Do you have CCC? I ask because it does have a 10.8 & 10.9 recovery maker inside of it.
Click to expand...

I don't have a paid copy of CCC but I have used the trial before to make a recovery partition (it actually clones the contents of an existing recovery partition).

However I didn't want to do that, as I wanted to make sure it was a freshly created recovery partition made by the Mavericks installer, so that there would be less chance of their being problems with the recovery partition caused either by the previous use of FileVault2 or upgrading from Mountain Lion.
 
Good explanation. By way thanks for the fixed post to make a new Fusion drive.

I say this because people have been questioned on my suggestions that Apple changed something in DIY Fusion drives and the old DIY Fusion drives setups of the past are only for 10.8.x.
 
Last edited:
satcomer said:
I say this because people have been popping my suggestions that Apple changed something in DIY fusion drives and the old DIY Fusion drives setups of the past are only for 10.8.x.
Click to expand...

It was interesting that in the notes for Mavericks Developer Preview 3 it mentioned that Fusion Drives created with Mavericks DP3 are not compatible with Mountain Lion 10.8.4 or earlier. So something has changed with Fusion Drives in Mavericks.

However, I don't know whether this means that a Mountain Lion made Fusion Drive is *upgraded* when Mavericks is installed or whether it is left as is. Also whether the act of *upgrading* or running an older Fusion Drive causes the problems under Mavericks. Though if that was the case I would have expected there to be problems with the Apple made Fusion Drives as well.

For me it seemed to cause issues, but then so did creating a new clean Fusion Drive in Mavericks.
 
I am having similar trouble on a Late 2009 27" iMac, with a 120GB Samsung Evo (disk0) and Seagate Barracuda 1000GB (disk1), following the instructions here: http://blog.macsales.com/17624-os-x...tup-option-for-non-fusion-drive-equipped-macs

Everytime I try creating a fusion drive, and I have tried disk0 disk1 order as well as disk1 disk0, in case that was the problem, it uses mainly the HDD.

Once it seemed to be working fine (all this is according to iostat), was copying some stuff to new installation to test, then there was a kernel panic (related to bluetooth it seems) and the computer restarted. When it restarted it was only accessing the HDD again. Resetting the PRAM didn't help.

My recovery partition is on the HDD, that seems to be the default when installing 10.9.2.

Does anyone have any advice? Could it be incompatibility with the SSD or something at a hardware level? This is pretty frustrating.
 
DD saved my day, works perfectly for me now

Hello,
I had the same problem on a 24" 2006 imac in which I've just added a 120 Gb SSD throwing away the optical drive.

When showing iostat, I saw the SSD wasn't used at all :eek:

I've just followed Dark Dragoon's detailed steps to recreate my fusion drive and
YAAAAAAAAAAA! (sorry) everything works perfectly now :D

Great and many thanks

Sincerely
 
Bear said:
You would need a backup of your iPhoto library from before the updated version of iPhoto update the library format.
Click to expand...

That's not entirely true. You can do a rebuild photo database while booted in Mountain Lion and have that operate on the updated database. I've done it myself.
 
SSD needed wipe out or Trim Enabler

Hello,
the last couple of days where my worst Mac days so far. And I am with Mac for a couple of years now. I tried to speed up my mid 2011 iMac with a DIY Fusion Drive. The installation of the SSD (Samsung 840, 500GB) was not that much of a problem. But setting up the Fusion Drive was a little nightmare...

I followed the instructions on the internet to set it up. Everything seemed to be ok. I installed Mavericks on the new drive which worked seamlessly. And since I wanted to reconnect to my Time Machine backup I transferred everything from the Time Machine backup back onto the new Mavericks installation. That took about 12 hours (about 2TB via FireWire).
After starting it up for the 1st time it felt a bit slow but I thought that things need to "settle". It kept being slow. Using iostat and mkfile to create a big test file I realized that the SSD is not used at all. So I thought I had done something wrong and started the whole procedure again. No improvement. I also upgraded the firmware of the SSD.

Since installing the OS onto the Fusion Drive to be able to test it and then needing to erase everything to try something else is a bit tedious, I installed Mavericks on an old external USB2 drive. Now I could play around without needing to install the OS again and again. I always tested the Fusion Drive with iostat and mkfile 1000m. I tried different partition sizes, different drive orders, different drive names, wiping out the beginning of the disks using dd (as Dark Dragoon suggested). Nothing seemed to help.

What I noticed during some other tests was a slow write speed of the SSD (40 to 80MB/s). Some post suggested to use Trim Enabler and a wipe out to solve the speed problem of the SSD. At 1st I did not think that that could be the problem of the Fusion Drive but it seems that it was.

What helped was the following:
- remove the Fusion drive (diskutil cs deleteVolume and so on)
- install Trim Enabler and enable trim for the SSD
- use Disk Utility (the GUI version) to erase the SSD
- create the Fusion Drive again

It now uses the SSD when creating the test file! :) So happy about it, that I had to create an account here to share this info.

Just installing Mavericks right now. Hope it will still work, when everything is set up.
 
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