Are big SSDs relevant anymore?

[Bear]

...
Assuming HD and SSD keep their trajectory in terms of GB/$, and correcting for larger files in the future, does anyone really need more than 1/4 of total HD capacity to be SSD?

It all depends on what the person is using their computer for. For me a 512 GB SSD system disk and a 1 TB data disk would work for me. a 256 GB SSD might work for a little bit, but it would be too full and a high chance it would fill up much sooner than I would prefer.

The issue with the fusion drive for me is you have no control on what gets stored there and there are some things I care about speed more than others.

If I had a system with a 1TB HD and a 128GB SSD, I would use the HD as the system disk and use the SSD for what I needed the speed for.

 

[Arfdog]

If I had a system with a 1TB HD and a 128GB SSD, I would use the HD as the system disk and use the SSD for what I needed the speed for.

That is how the Fusion Drive is setup.

 

[Bear]

That is how the Fusion Drive is setup.

Ahh no it isn't. The fusion drive caches what it thinks the hotfiles are on the SSD portion of the fusion drive. You have no control of what OS X puts on the SSD with a fusion drive.

I want explicit control of what is on the SSD.

 

[auhagen]

There are thousands of things that the OS manages for me. This is one more. CoreStorage can split files much more effectively than you or I can. I would rather get on with looking at important jpegs of cats than spend my time inefficiently moving files around.

Let's say you have a large bunch of files that all need to be in the same folder. But you only use a few of them often. CoreStorage can move the files (or sub-file blocks) that you use a lot onto the SSD, and keep the ones you don't use on the HDD -- and maintain the same file/folder hierarchy on the volume.
Most people probably use 20% of the files on their disk 80% of the time. CoreStorage works on this, on a block level.

Well call me old school, but I still like to do it manual like this:

SSD:
System
- OSX
- Win7 (cad software)
- Apps
Files
- Documents
- Photos
- Downloads

Hdd:
Files
- Music

 

[Nuke61]

Ahh no it isn't. The fusion drive caches what it thinks the hotfiles are on the SSD portion of the fusion drive. You have no control of what OS X puts on the SSD with a fusion drive.

I want explicit control of what is on the SSD.

It doesn't just cache what it "thinks" are the hot files, it does so based on actual file access. The most accessed files stay on the SSD, with no need on my part to try and keep track of what files I'm opening or not opening.

So yeah, if you want to put system files on the HDD portion, even though they might be more heavily accessed, you have to split it. Me? I'd rather have files on the SSD that I access more frequently, whether they are system files or user generated files.

 

[JustMartin]

It doesn't just cache what it "thinks" are the hot files, it does so based on actual file access. The most accessed files stay on the SSD, with no need on my part to try and keep track of what files I'm opening or not opening.

So yeah, if you want to put system files on the HDD portion, even though they might be more heavily accessed, you have to split it. Me? I'd rather have files on the SSD that I access more frequently, whether they are system files or user generated files.

I'm with you. I'm happy that what I'm accessing most frequently is going to the SSD. I guess I can imagine a scenario where you might want real quick access to a file about once a year (i.e after it's been aged to the hdd), but I can't see it being a common requirement.

 

[benwiggy]

Ahh no it isn't. The fusion drive caches what it thinks the hotfiles are on the SSD portion of the fusion drive.

For the fiftieth time, Fusion drive is NOT caching. If you don't understand this, then there is no hope.

SSD:
System
- OSX
- Win7 (cad software)
- Apps

Even those parts of the OS X installation that you never use?
Fusion drive can move the system files that you rarely use to the HDD and use that space for files. It can even move some data blocks of files within app packages to the HDD and keep other blocks in the app package on the SSD.
You can't do that.

 

[Bear]

For the fiftieth time, Fusion drive is NOT caching. If you don't understand this, then there is no hope.
...

I understand what it does. Using the word "caching" was apparently not the best choice of word to use. However, it's still a caching style algorithm even if it is the only copy of the data on the disk.

 

[Arfdog]

Ahh no it isn't. The fusion drive caches what it thinks the hotfiles are on the SSD portion of the fusion drive. You have no control of what OS X puts on the SSD with a fusion drive.

I want explicit control of what is on the SSD.

How does it determine what it thinks should be on the SSD? Does it guess randomly and just hope it's right? Don't think so.

Not to be as a$$, but this is a bit like demanding explicit control of the HDD like defining which drive is slave and which is master. Or manually parking the read/write head. Or setting fan speeds manually based on what you see from the temperature gage.

Since the speed is the same between fusion and SSD 95% of the time, is your time better spent managing where files go or actually using them?

 

[Nuke61]

I understand what it does. Using the word "caching" was apparently not the best choice of word to use. However, it's still a caching style algorithm even if it is the only copy of the data on the disk.

It doesn't sound like you understand what it does, or you're doing a poor job of explaining it so it sounds like you understand it. A cache explicitly implies that the storage on faster device is purely temporary, and whether it's still in the cache is based simply on time. Enough time passes, and the file is no longer in the cache. Tiering is based on usage, not time, so it's not just another caching style algorithm.

If a file is accessed often, it will live on the SSD in a tiering setup, no matter how much time passes. The same is simply not true in a caching setup, no matter which algorithm it uses.

 

[phrehdd]

Once again: Fusion is NOT caching. It is tiered storage. A completely different concept. Fusion continues to provide benefits when the SSD portion is full. Because the bits that are on the SSD can change according to your use.

Ever work with music files, video or photos? Most know that one goes many times with the same large files and exactly how does Fusion handle this? Fusion might work well for a typical user but it is indeed "ordered" application set up that will be limited by the amount of items repeatedly opened and used.

Again it is not much different in functionality to Seagate's offering if one uses the set up for repetitious opening of larger files within applications.

 

[Nuke61]

Again it is not much different in functionality to Seagate's offering if one uses the set up for repetitious opening of larger files within applications.

128GB vs 4GB or 8GB is a pretty big difference, particularly if discussing large files. Additionally, the XT's NAND cache is read only... it provides zero benefit for writes.

 

[calaverasgrande]

IMHO: Processors and RAM are getting so fast that we are waiting on the HD. So even if HDs get even cheaper, most people will opt for the SSD. Also SSD uses a fraction of the power of an HD, so you get the longer battery life, and less heat too.

actually that isn't always true. Some SSDs are lower power than a hard drive. But while they were ramping up SSD produciton, HDD makers have been "going green" by making their hard drives more power efficient.

There was an anandtech or tomshardware article a while back...

 

[Arfdog]

Again it is not much different in functionality to Seagate's offering if one uses the set up for repetitious opening of larger files within applications.

That's a joke right?

 

[benwiggy]

Ever work with music files, video or photos? Most know that one goes many times with the same large files and exactly how does Fusion handle this? Fusion might work well for a typical user but it is indeed "ordered" application set up that will be limited by the amount of items repeatedly opened and used.

It works with data blocks, not files. There has been extensive coverage of how Fusion works on sites like Ars Technica.

 

[bingeciren]

On the practical side of things.

Long before the Fusion was introduced, I was managing my files manually on my Mac Minis. I have 2 Mac Mini servers and I use them as media servers rather than true OS X servers. I replaced one of the drives with a 128Gb SSD on each one and use the 500Gb HD as the media storage and the SSD for OS X, programs and Parallels VM files. I replaced the system folders like the Downloads, Music, Pictures and Movies with Symlinks so that my home folder appears as if I have one drive and all my files reside in the same place. So far so good, I have the full control. Then I got curious and wanted to experiment with the DIY Fusion drive just to see how it compared with my manual setup. I converted one of the Mini to Fusion. I have been using it for a month now and I'm so impressed with the performance that I'm going to convert the other Mini as well. Aside form the speed, the biggest advantage I gained by converting to Fusion is the management of the empty space in the SSD portion. With two drives, you always have and empty portion on the SSD as well as on the HD, and you have to watch that you don't run out of room on the SSD as the page file resides there. With Fusion, I don't care. It is just like having a single drive. As a result, you can utilize the combined drive space more effectively. If you think you can manage files manually better than Fusion, than how about managing the system memory, system cache manually as well. Even better if you had manual control on a Hybrid Drive, would you care to manage the blocks yourself between the Flash and the HD portion? I don't think so. I abandoned my old school of manually managing my files and relinquish the control to the Core Storage and I am very happy with the result.

 

[Mike in Kansas]

Integrating internally and externally attached storage into a coherent user experience might however be something worth considering in the future. I don't really feel that operating systems concern themselves with the recent development of pretty much everybody having at least one external hard drive by now. We need 'Fusion Drive - Phase II' or whatever to take care of that.

You can "fuse" any 2 drives together regardless of whether they are internal or external to get that "coherent" user experience. I am running a "roll your own" Fusion array on my 2008 iMac using an internal 240GB SSD and external 2TB FW800 HDD. To me, it looks like 1 big 2.24TB volume and the user experience is awesome. So much better than keeping my OS, apps and "important" files on my internal SSD, my music, photos, libraries, etc. on my external HDD, and manually shuttling things back and forth to optimize my UX in, say, Aperture. It now operates like 1 big 2.24TB SSD in most instances.

 

[Giuly]

You can "fuse" any 2 drives together regardless of whether they are internal or external to get that "coherent" user experience. I am running a "roll your own" Fusion array on my 2008 iMac using an internal 240GB SSD and external 2TB FW800 HDD. To me, it looks like 1 big 2.24TB volume and the user experience is awesome. So much better than keeping my OS, apps and "important" files on my internal SSD, my music, photos, libraries, etc. on my external HDD, and manually shuttling things back and forth to optimize my UX in, say, Aperture. It now operates like 1 big 2.24TB SSD in most instances.

Try unplugging it, as you'd do on-the-go with a MBP. 😉

The idea was rather something akin to what happens when you hook up a camera to an iOS device: Your photos just show up in the Photos app, unplug it and they're gone. Yet what I had in mind went further than that and would (continuing with the example) unify both the photos on the camera as well as those on the iOS device into a single camera roll.

That, but in a more generalized way across all applications on a Mac, akin to a revamped file picker that puts all your files suitable to be opened in a particular application in a single place with means to organize them right in the application rather than scattered across traditional folders. Pages on iOS provides an example for this, if you'd look at iCloud as a fancy external hard drive.

The laziest way of doing this would be by associating a folder on the boot drive with a folder on an external hard drive (identified by UUID), then setting up symlinks to the folder on the boot drive when the external hard drive is connected via a daemon that runs in the background, and remove the links after the drive was ejected. If you were to connect the drive to a different Mac, the files would show up normally, sans the ones on the boot drive.

This seems so trivial that you can probably download something from the Mac App Store with this kind of functionality already.

 

[jjhoekstra]

.

Moreover, 1TB is the maximum for 2.5"HDD, the technology wont grow anymore. But SSDs will, there are already 2TB 2'5" SSDs and bigger to come

I will tell my newly bought WD 2TB 2.5" HDD that it does not exist... 😉

Having corrected that, I do think that spinning disks will disappear faster than we can imagine right now. Like the good old floppy, suddenly it just disappears.

 

[gnasher729]

HDD development is already slowing while SSD tech is excellerating rapidly. Fusion is a nice stop gap until SSD surpasses HDD in price and capacity, but really won't be needed in 3-5 years except for maybe a combination of different types of SSD devices.

Seagate has stopped development of 7200rpm 2.5 drives.

There's the question for how long SSD drives can continue to grow. The number of charges in a single bit cell has been going down rapidly, and there are limits that can't be crossed. It is entirely possible that we will hit a wall soon. The number of possible writes to SSD has gone down in the last years, and eventually some now technology will be needed.

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Ahh no it isn't. The fusion drive caches what it thinks the hotfiles are on the SSD portion of the fusion drive. You have no control of what OS X puts on the SSD with a fusion drive.

I want explicit control of what is on the SSD.

But why? Fusion puts the blocks of data onto the SSD that give you the most benefit, and leaves those out that don't give you any benefit. Like the two printer drivers that you use on SSD, the 198 that you don't use on HD. Almost all directories on SSD, and almost all small files on SSD (small files give the most benefit). When you open iTunes with a 20,000 song library, all the album art is on the SSD and the rest of the music is on the hard drive. With your applications, 1 language on SSD and 19 on the HD.

Fusion includes a 4 GB write cache. Which means up to 4 GB of write operations are super fast at maximum SSD speed, and when you're done Fusion sorts things out and puts everything where it should go. And it uses 99% of your SSD, not 60% or 70% as a human user would.

 

[jdiamond]

Two points not yet mentioned...

Just thought I'd mention two points about flash SSDs not yet mentioned in this thread:

1) Flash scaling is almost done. Sandisk has publicly stated there will be only 2 more nodes of flash before they have to go to exotic technology the same way conventional drives have. Notice how many years it took for flash to drop from $3/GB to $1/GB. You may never see much below 50 cents/GB. You're certainly not going to see an $80 1TB flash drive.

However, as mentioned, that's not such an issue, as most people are fine paying several hundred dollars for a hard drive if its size is sufficient. Cost per GB only matters until we can afford the size we need. 🙂

2) Flash has issues. It doesn't last as long as a hard drive and is harder to replace. As its density goes up, reliability is dropping. And while as a whole, people usually see speedups with flash drives, flash drives have extremely poor performance at reading small blocks (because they have a minimum granularity), and their performance degrades much faster as they fill up (due to wear leveling.) This isn't arm chair philosophy - I have an OWC SSD and I watch as some folder copies (the ones with lots of small files) fall down to as far as a few KB/second! So ironically, the area where flash gives its largest advantage (seek speeds) is neutralized by its fundamentally large block size. So I'd say that flash SSDs have a much larger variation in performance.

I've also seen terabytes of data lost on MLC flash - luckily, it was backed up on hard drives, but had I not noticed the files contained garbage it would have been different. To be fair, DVD-Rs have similar longevity issues. But I've been a heavy user of data backup for a long, long time now, and real hard drives are by far the best.

Ironically, what you want right now for reliability is a hard drive in your laptop and a flash backup drive. The most reliable medium need to be the source. If the flash backup drives fail, it's less critical - you might never need the backup, and every day you overwrite the files with a good version. But if your laptop files get corrupted, it doesn't matter if you back them up to high quality hard drives, because before you notice, you will just overwrite the backup with the corrupted files.

 

[auhagen]

Even those parts of the OS X installation that you never use?
Fusion drive can move the system files that you rarely use to the HDD and use that space for files. It can even move some data blocks of files within app packages to the HDD and keep other blocks in the app package on the SSD.
You can't do that.

Your joking right? OSX is not using a whole lot of space on the drive. And ssds are cheeper than ever, so it's nothing that concerns me. My files and programs together only uses about 150gb op space, my movie and music collection, is a whole other story, hence there fore its on a hdd and my nas. The only thing I dont have full speed for is movies and music, and why the hell do I need speed to play those?

 

[benwiggy]

Your joking right? OSX is not using a whole lot of space on the drive. And ssds are cheeper than ever, so it's nothing that concerns me. My files and programs together only uses about 150gb op space, my movie and music collection, is a whole other story, hence there fore its on a hdd and my nas. The only thing I dont have full speed for is movies and music, and why the hell do I need speed to play those?

What's your point? If you have 150Gb of stuff and everything is on an NAS, then you don't need a Fusion Drive.

If people need HDD-sized storage with SSD speeds, with automatic tiered storage at block level, then Fusion Drives represent a useful option. And it is more efficient at moving files than people.

 

[auhagen]

What's your point? If you have 150Gb of stuff and everything is on an NAS, then you don't need a Fusion Drive.

If people need HDD-sized storage with SSD speeds, with automatic tiered storage at block level, then Fusion Drives represent a useful option. And it is more efficient at moving files than people.

Well I told how my setup was, and you asked the questions. I stated that i liked my setup more than fusion, and I was the master over my files. That way all that need speed is on my ssd, and multimedia files is on a traditional hdd.

Fusion cannot do that, by any means. Not yet..

Yes Fusion is not for me, but I still like my method better, than software that makes decisions for me, based on my use.

Thats my point..

 

[Mike Valmike]

What if HDDs also go to a lower dollar point?

They will/should/can. But it might not matter. Part of why spinning drives are still used at all right now is for video, which had gotten fairly manageable in size at SD but then got very big again in HD. Not just people keeping drives full of bootleg downloads/legit rips, but professionals editing and producing video. If video wasn't a factor, our modern 256GB SSDs would probably suffice for all but a tiny niche of archivist users -- who would just have a RAID of more than one of them.

The next step is 4K video, and the size curve on SSDs is moving so quickly that they might be cheap and ubiquitous in time for 4K to become prevalent. By the time we have full holodecks and such, I'm sure we'll be storing the stuff on superconductive fusion cubes or some amazing thing. But it won't make sense along that progression for usage to revert to spinning platter drives.