Create Fusion Drive for Mac Mini?

Wow didnt know the trim enabled would mess the os yosemite does that mean also like a third party ssd drive like Samsung 850 pro enabling trim would be a bad idea in Yosemite with a fusion drive setup? Iam a bit concerned now, or is this exclusively for owc

Soundwire wrote:

does that mean also like a third party ssd drive like Samsung 850 pro enabling trim would be a bad idea in Yosemite with a fusion drive setup? Iam a bit concerned now, or is this exclusively for owc

Samsung SSDs are fine with TRIM enabled. I used TRIM on a Samsung 840 Pro with no issues in a Fusion drive within Mountain Lion and Mavericks. But BEFORE you try to enable TRIM in Yosemite, you should read up on any issues with TRIM. I think there are some concerns with kext file signing.

Intel and OWC use the SandForce controllers and OWC states TRIM is not needed with their drives. Crucial doesn't seem to have an opinion with enabling TRIM on their SSDs that I can find. But I don't use TRIM, period, for any 3rd party SSDs. Personally, I don't do enough file activity to be concerned. And the built in Garbage Collection with OWC, Intel, Crucial and Samsung SSDs fit my needs.

keg55:

I'd concluded that the OWC SandForce drives were least likely to cause headaches with Yosemite, but I hadn't read about data corruption issues. Thank you for mentioning that! I'll look into the frequency of the problem.

Soundwire:

That's what bothered me too. I've read mixed reviews about Samsung and Crucial drives in Macs with respect to TRIM and Yosemite. Some say they use them without any issues; others say they run into freezes, crashes, and slowdowns. As I understand it you can install a TRIM enabler, but to do so you need to override a security feature built into Yosemite.

I ultimately returned the refurb 2012 Mac Mini I bought in early December 2014. With its stock 5400rpm drive it was no more responsive than a 2007 iMac or even a 2006 MacBook with a 7200rpm drive, and installation of an SSD meant a tricky and delicate procedure that not infrequently damages internal components. It's a pity Apple has sacrificed easy user upgradability for miniaturization. In my opinion it's a poor tradeoff.

Installing a 2nd drive in a 2012 Mac Mini can be an intimidating upgrade, but I found taking one's time and viewing videos at iFixit.com and OWC, it wasn't so bad. The ONLY issue I had with 2 - 2012 Mac Mini's (one new, one refurb) was making sure I had a compatible SATA cable. I had to use the stock Apple cable with the SSD on both and a 3rd party (iFixit or OWC) with the stock HDD. I purchased the iFixit tool kit for disassembling the Mini to add the 2nd drive. It was well worth it adding an SSD.

Both of my Mac Minis are used as servers. Both running OS X Mountain Lion and OS X Server 2.2.5. One is setup as a Fusion drive and the other - non Fusion -has the OS with some frequently accessed files on the SSD. The HDD is used for file serving, music and a clone of the SSD.

Re installing a second drive: That's what I've read elsewhere. I decided not to chance it with the Mini because it seems simpler, cheaper, and better suited to my needs (I don't need a server setup) to pick up a 2011 or 2012 MacBook and slip an SSD into that. I use late-model MacBook Airs a lot, and I agree, an SSD makes all the difference. The Mini with a stock 5400rpm drive seems impossibly slow even though it's an i5 with a faster clock speed than the Airs or even the much older spinning-drive machines I compared it with. What I really scratch my head over is why Apple feels compelled to manufacture what is essentially a desktop computer (the Mini) with a footprint and internal component space so small that it's risky to upgrade it. But that is another discussion.

Jonathan Brown wrote:

What I really scratch my head over is why Apple feels compelled to manufacture what is essentially a desktop computer (the Mini) with a footprint and internal component space so small that it's risky to upgrade it. But that is another discussion.

Agree.

Have you seen the teardown on the 2014 Mac Mini model? Others are scratching their heads on how difficult it is to get inside it to DO an upgrade along with soldered on RAM. And once inside there's only 1 SATA port and a PCIe port for a blade SSD. 🙂

Yes it is really unfortunate Apple made that move. Really makes me angry..

Keg55:

Ya so when I set up a fusion drive with my new ssd, I need to disable trim before I upgrade to Yosemite, which I think is obviously unnessecary because I use a hdd trim is already disabled, however I just have to make sure that I have trim still disabled in Yosmite with the new SSD in boot. Dont really know what might be consequences for that other than I have read that it would wear down my ssd speeds. Do i really need to have the TRIM enabeld is the real question, i guess i just might wait and see, and if so slow speeds and errors i think i might still risk enabling trim in yosmite, when that happens. Or i could just downgrade my OS. Unfortunately.

Whether it arises from a Steve Jobs–inspired fetish for slimness, irrespective of whether it is situationally appropriate, or a willful attempt to turn out only prematurely obsolete, disposable consumer goods from which only Apple can extract revenue, I can't say. Whatever its rationale, what I can say is that, for all the convenience of Apple's ecosystem, I'm not all that happy about it, and the hacker-centric enterprise that Apple began as way back in the 20th century seems practically unrecognizable in the financial and entertainment colossus of the 21st. But that too may change, or so I hope.

Soundwire:

I did not know this old thread is still "alive".

Trim: no for the modern SSDs Trim is not necessary: all have good controllers with efficient and capable GarbageCollection. With these SSDs there is a chance that there will be timing problems on the the file level transfer. Thus you take a (small) chance on issues while it does not contribute. OWC just takes a firm standpoint the other manufacturers are a bit evasive about it.

The Samsung 850 EVO PRO is a new generation (the best at this moment) and does not need trim at all: it has large overprovisioning and a very intelligent controller (a bit better that the Marvell controller even): it has the best GarbageCollection.

Fusion: as I said about half a year ago: the story is great but was made in a period that SSDs were expensive, so it became practice to combine a small SSD and a large HDD. The Fusion system is constantly changing the location of files without giving them a fixed location. This may sound great (the most used on the SSD and the rest on the HDD), but what to think that the SSD now has more writes and reads and thus does more GarbageControl to keep the SSD fast. What to think about the work of TimeMachine and other backup software? Fusion was a great story for an intermediate two/three years.

Alan: of course your system will not die faster than a larger SSD (with or without a HDD for the movies and music and photo libraries). But without FusionDrive the SSD is less stressed, that is for sure.

Lex

Ok, see what you mean, and actually i have also just called Samsung about this problem. They said that the earlier model could have problems in yosmite, but not the 850 PRO / EVO, because of the good controllers, like you said. Also they said that only if I write more than 4G p/day, it would effect my samsung in the long term without trim, unfortunately, i don't know what is the normal standard but i guess it is well over the normal standard and if i have fusion, would it be well over that limit i guess?

And if fusion drive would put strain on my SSD, i think i will go for the normal setup, my HDD and SSD separate, and just use Symbolic links instead.
Also i don't think 256 GB SSD would be enough for me, in that time i would then do some clean up.

....Also they said that only if I write more than 4G p/day, it would effect my samsung in the long term without trim....

They forgot the word continuously

Indeed, you will never reach that continuous writing level, but with a FusionDrive that level will be reached earlier....

If you have any doubt about the overprovisioning (like with the non-pro SSD) do following when you format the SSD before installing the OS: make 1 partition and make it a bit smaller than the maximum capacity (say 25GB smaller) so that that 25GB is not formatted ! The SSD controller will use that as extra space for the GarbageCollection activity (this is advised by OWC). But as I said this imho only contributes for other SSDs than the 850 EVO PRO, and then only when you use the SSD as a server.

Lex

Ok so let me get this straight, that last part you said, creating smaller partition is not needed if it doesn't contribute to the EVO/PRO Samsung garbage collection, but only to other SSD's, but i should still do it, just in case. 🙂

If you do not use the SSD in a server, I would not do it.

Just remember that on any SSD, it is better to have some more free space than is advised for HDD. I always make sure that at least 40-50GB is free space (and on a HDD 25-35GB). But except for one installation I never left space unused (unformatted); that one installation is a technical installation supervisor that runs day and night and is very very loaded.

Lex

PS: the exceptional EVO PRO is just temporarily an exception: others will follow.

Soundwire,

Here's some more information to chew on regarding over provisioning your Samsung 850 Pro 256GB SSD. The article from Samsung references the 840 models but I feel it also applies to the 850. I have followed their advice as far as how much which is 7-10% of the total size. So for your 256GB, 25GB is plenty for over provisioning. On my Samsung 840 Pro, 128GB I went with 7% or roughly 8GB. OWC and Crucial M500 SSDs already have over provisioning built in. For example, both have a 240GB SSD. So,16GB for over provision. That's within the 7-10% range. I have not added more for those drives.

There's nothing wrong with over provisioning more space as LexSchellings advises. It's up to the customer and 7-10% seems to be the advised norm.

By the way, Samsung SSDs (in my opinion) are the fastest of the SSDs I've used (Intel, Crucial, OWC, Samsung). And the 850 you are getting is excellent! Regarding TRIM, you decide what you want to do in that regard. We can only give our opinions and experience. 🙂

Kegg55 and LexSchellings:

Yes i am really happy to have 850 Pro, can't wait to try it out 😝, if there is a substaintial slow down regarding to TRIM disabled, using any SSD, just downgrade your OS X to mavericks, iam fine with that. Regarding provisioning i am not into OP, as i do not use SSD in a server, so that is not a necessity for me, i only use it for productivity personal use. So i don't really need to partition, with the 850 Pro i think it can handle the strain, it is an exception.