The second problem with the technology is the relatively high cost of a hybrid drive - for a 128 GB SSD, the buyer will have to pay at least $ 250, which is more expensive than third-party SSDs. Moreover, prices for more spacious ones are falling, which is why advanced users have more options. Many people will appreciate the simplicity and convenience of the Fusion Drive, but most likely, only a few will be happy to pay extra for it.
You should also not forget that many users no longer need a capacious drive. Macs are gradually losing the title of “digital hub” that Steve Jobs once endowed them with, more and more multimedia content is available in cloud services, and a large HDD is not needed to view it (Apple TV does an excellent job with these tasks). It looks like Fusion Drive is trying to solve a problem that by and large doesn't exist.
The technology also has other problems, for example, the flimsy software implementation of Core Storage, due to which the logical volume often becomes unusable and needs to be restored from scratch
Fair, not too high or too low. There should be prices on the Service website. Necessarily! without "asterisks", clear and detailed, where it is technically possible - the most accurate, final.
If spare parts are available, up to 85% percent of complex repairs can be completed in 1-2 days. Modular repairs take much less time. The site indicates the approximate duration of any repair.
Warranty and Liability
A warranty should be given for any repair. Everything is described on the site and in the documents. A guarantee is self-confidence and respect for you. A 3-6 month warranty is good and enough. It is needed to check the quality and hidden defects that cannot be detected immediately. You see honest and realistic terms (not 3 years), you can be sure that you will be helped.
Half the success in Apple repair is the quality and reliability of spare parts, so a good service works directly with suppliers, there are always several reliable channels and a warehouse with proven spare parts for current models so that you do not have to waste extra time.
Free diagnostics
This is very important and has already become a rule of good form for the service center. Diagnosis is the most difficult and important part of the repair, but you should not pay a dime for it, even if you do not repair the device after it.
Service repair and delivery
A good service values your time, so it offers free shipping. And for the same reason, repairs are carried out only in the workshop of the service center: it can be done correctly and according to technology only at a prepared place.
Convenient schedule
If the Service works for you, and not for itself, then it is always open! absolutely. The schedule should be convenient in order to be in time before and after work. Good service works on weekends and holidays. We are waiting for you and working on your devices every day: 9:00 - 21:00
The reputation of professionals consists of several points
Age and experience of the company
Reliable and experienced service is known for a long time.
If a company has been on the market for many years, and it has managed to establish itself as an expert, they turn to it, write about it, recommend it. We know what we are talking about, since 98% of incoming devices in the SC are restored.
We are trusted and passed on complex cases to other service centers.
How many masters in the directions
If you are always waiting for several engineers for each type of equipment, you can be sure:
1. there will be no queue (or it will be minimal) - your device will be taken care of immediately.
2. You give Macbook repair to an expert specifically in the field of Mac repairs. He knows all the secrets of these devices
technical literacy
If you ask a question, the specialist must answer it as accurately as possible.
To give you an idea of what you need.
Will try to solve the problem. In most cases, from the description, you can understand what happened and how to fix the problem.
Recently purchased an iMac with 2TB Fusion Drive. It comes with 128GB of high-speed PCI SSD memory (read speed up to 3000MB/s) and a conventional but capacious 2TB hard drive (read speed up to 200MB/s).
Fusion Drive combines them into a single virtual drive and automatically distributes frequently accessed files to the SSD. The result is an instant launch of programs and the system. What are the downsides?
I began to notice that the system was sending photos and videos from the Photos application, tool libraries from Logic Pro and other files to the SSD that I use often, but they take up a lot of space.
I personally don't care how many milliseconds a photo or tool opens faster. With such an algorithm, 128 GB (or 32 GB in other models) can overflow, and then the brakes will start where it is not needed. Over time, many users report slow Fusion Drive performance, especially when disk space is running low.
Yes, the Fusion Drive algorithm is not perfect and cannot be perfect.
But we can help him.
And manually free up extra space on the SSD.
Stupidly dragging files to the HDD will not work: in the system we see only 1 logical drive, we don’t know what and where is located in it. You can only make assumptions based on the speed of launching and opening certain files. But there is another way.
You can use Disk Utility to separate some of the free space on your hard drive from the Fusion Drive. Yes, it's the hard drive. As a result, we will get a new partition, all files on which will be placed exclusively on the HDD, without affecting the SSD area. Next, we transfer there everything that takes up a lot of space and does not need to be launched instantly. It turns out a familiar scheme: the system and applications are stored on the Fusion Drive (SSD), and everything else is stored on the hard drive.
You need to select Fusion Drive in Disk Utility and create a new partition on it. Everything. For the safety of data, all manipulations are best performed from a bootable USB flash drive.
What can be thrown on the HDD. Folder shortcuts
Here are some examples:
System folders
Use labels. For example, almost any system folder with content (movies downloaded from iTunes, backups, and so on) can be transferred to a hard drive by first creating and leaving a redirect shortcut where the folder was previously located. How to do this, read below:
iPhone and iPad backups in iTunes
On this topic, I published a separate article with detailed instructions. In the same way, you can transfer to the hard drive and other system folders. This is how I moved the Logic tools to the HDD.
In short:
1. We find a heavy folder with content on the system drive (Fusion Drive).
2. Copy the folder to your hard drive.
3. We delete the folder from where it was located earlier, and in the same place we leave the redirecting shortcut instead. Every time a program accesses the system drive, the shortcut will redirect it to the hard drive. iCloud Photo Library (photos and videos)
For example, about 5000 of my photos are stored in iCloud and automatically synced with all devices. That's 60 GB of data, and they don't belong on an SSD.
The library is located in the system Images folder and is called Photos Library, just drag this package to your hard drive, open the Photos application and select it as the main library.
As well as…
Photos, videos, and movies not stored in iCloud. Instruments, plugins, sample libraries. Music collections. Download folders.
If you receive notifications about the lack of free space while working with Photoshop, you can select the HDD as a working disk in the settings.
Look, just uninstall the Fusion Drive and get on with your life.
Yes, it is possible to disband Fusion Drive completely. Manually transfer heavy files to the HDD, install the system and programs on the SSD and not worry.
But in fact, 128 GB, not to mention 32 GB, is not enough. The system constantly gets notifications about the lack of space, some heavy programs create a huge cache on the disk during operation, and the hemorrhoids become three times larger.
Personal experience, I already had one such computer. Users who use a Mac only for Internet access, photo editing and some everyday tasks may not be affected. But for creative activity and large-scale projects, this is a barrier.
P.S. If you allocate space very competently (including using the tips from the article) and do not download a bunch of software, 128 GB SSD-only will be enough. But definitely not 32 GB.
What would be perfect:
Leave 512 GB Fusion Drive (128 GB SSD + 384 GB HDD) and 1.6 TB hard drive space for files.
512 GB is more than enough for seamless system operation, running heavy programs and projects. There will be no problems with lack of space.
For less demanding users - 256 GB Fusion Drive (128 GB + 128 GB), the rest under the HDD. New Macs configured with a 1TB Fusion Drive only ship with a 32GB SSD. In this case, it is better to leave 256 GB for the Fusion Drive, and use the rest of the HDD space for files.
Now all new Mac models with 1TB Fusion Drive come with a 32GB SSD. For a 128 GB SSD, you need a 2 TB or 3 TB Fusion Drive. But some older models with 1TB Fusion Drives have built-in 128GB SSD brackets.
Is there a need to do all this?
Not always. If the speed of the Mac is completely satisfied, you can not bother. But this is an additional order in the operation of the computer, and it will not be superfluous. Only benefit. Especially for models with 32 GB SSD.
Yes, the soul of the geek wanted to completely separate disks and distribute files manually. But the 512 GB Fusion Drive + HDD turned out to be the ideal option both in terms of speed and amount of free space. I don’t see a sharp need to wait and overpay for a custom iMac assembly just for the sake of a capacious SSD. Moreover, in the 2017 models, its read speed is identical to the SSD on the Fusion Drive.
Contrary to the expectations that the appearance of the first SSDs in consumer devices caused, it is now quite clear that a total transition to solid state drives is not possible in the foreseeable future. Manufacturers of NAND Flash memory have made great strides in terms of reducing the cost of chips, but the price of a gigabyte of capacity on magnetic disks is still an order of magnitude lower than on SSDs. In addition, with each step of Flash-memory to a “thinner” production rate, it is increasingly difficult to ensure the reliability of reading the charge in the cell and the required number of rewriting cycles. Hard drives, on the contrary, still have an inexhaustible reserve for increasing capacity in a standard design with the usual GPP / GMR heads (Perpendicular to Plane / Giant Magnetoresistance) and several exotic technologies in the future.
Flash memory is most widely used in mobile devices, where the advantages of solid state drives fully justify the higher price per unit volume. If we talk about Apple, then as a manufacturer of undeniably expensive equipment, it can install SSDs in computers that compete with hard drives in terms of capacity, which we see in the top configurations of the MacBook Air and MacBook Pro with Retina Display. And the only Apple mobile device that still comes with a hard drive is the aging MacBook Pro without a retina.
In desktop computing, it's not easy even for Apple to drop a hard drive as a base storage option. While the Mac Pro (fully converted to SSD) has limited savings, all three of the base iMacs Apple now makes have a 500GB-1TB hard drive. There are full SSD options up to 256GB or 512GB that require an additional $200-$500 investment over and above the TB HDD configuration. And between these extremes is Fusion Drive, which is an array of 128 GB SSD and 1 or 3 TB hard drive. Upgrading a Mac to a Fusion Drive combined with a terabyte drive also costs $200, so it's not an easy choice. About him and will be discussed.
Note. Pricing shown is for the US Apple Store. In Russia, an upgrade with a 1TB HHD to a Fusion Drive costs 7,960 rubles.
To be honest, the author of this article has not been expecting anything good from hybrid drives for a long time. So far, none of the solutions tested in 3DNews has come close to the goal declared by manufacturers - to combine SSD performance and HDD capacity with an affordable price. Most of the "hybrids" are built according to a single scheme: a small solid-state component is used as a cache, in which frequently requested information is duplicated from the main drive - HDD. In some cases, the SSD is also used for write caching. It is assumed that after a certain period of adaptation, the cache begins to duplicate the most common data - OS and application files, and the blockages of rarely used resources remain on the HDD. In this concept, it is natural that the larger the solid state component of the hybrid drive, the higher the average performance. For example, 8 GB of Flash memory, soldered on Seagate SSHD drives, is clearly not enough to make the system as responsive as full solid state storage. At best, we can talk about an intermediate position of this kind of "hybrids" between SSD and HDD, although in numerical terms - not even an average.
A more efficient approach is implemented in Intel Smart Response Technology, which allows you to use a single SSD up to 64 GB as an SSD cache (provided that the system is built on one of certain Intel chipsets). But at the same time, the price is rising, and for this reason, few of the finished computers and laptops enjoy such a luxury. Finally, with a fairly large SSD, the thought already arises: shouldn’t caching be abandoned and taken entirely under the OS and programs as a separate volume? Actually, this is what they did with the WD Black 2 drive, which is a terabyte HDD and a separate 120 GB SSD in one case. But again, savings on SSD components, multiplied by raw software, does not allow us to cite the WD Black 2 as an example of a successful hybrid drive.
⇡ Meet Fusion Drive
So what can Apple add to this? The Fusion Drive recipe is basically the same as that Jew from the joke: "Put more tea leaves." The role of the solid-state component of the array in Macs is 128 GB SSD, and, importantly, with high-quality controllers.
In principle, this in itself is a satisfactory configuration for comfortable work. With some discipline, you can keep the OS and all your running files within a 128 GB SSD (ask MacBook Air users), and manually store your media library and other heavy resources on your hard drive. However, Fusion Drive is what Fusion is for, that SSD and HDD are combined into an array. In this case, the end result depends on how the SSD is used.
Apple iMac 21.5" Mid 2014
The total volume of the array is equal to the volume of the individual components. We tested a 21.5-inch iMac and in our case that's 1128 decimal GB (1TB HDD plus 128GB SSD). That is, we can immediately say that the data is not duplicated, the SSD does not perform the function of a cache. Instead, there is tiering: frequently requested data goes to the SSD, stale data goes to the HDD. Q: How are priorities determined? But more on that later.
⇡ Fusion Drive: Components
First you need to understand what kind of iron we got. iMac and Mac mini models prior to 2013 used variations of the Samsung PM830, not the worst SATA 6 Gb / s drive. Now Apple has introduced SSDs with a native PCIe interface everywhere, which promises a significant increase in performance. Hard drive - 1 TB in 2.5-inch form factor for younger iMac and Mac mini or 1-3 TB in 3.5-inch form factor for 27-inch iMac.
The System Information utility gives you the manufacturer of the SSD. Judging by the name APPLE SSD SD0128F, this is the same SanDisk drive found in the Mac mini, as well as the 2014 MacBook Air and MacBook Pro with Retina Display. It is possible that the alternative that Samsung supplies may also come across in the Fusion Drive configuration. Both drives are connected via PCIe 2x interface.
SanDisk SSD, photo iFixit
The SanDisk SSD is based on the Marvell 88SS9183 controller, which we previously met with the Plextor M6e example. The chip has a native PCIe interface with two lines of version 2.0, it transmits data using the AHCI protocol (unlike NVMe, which is specially designed for solid state drives). Eight channels are provided for connection with Flash-memory chips. Of course, the TRIM command is supported.
The SSD itself is made in a proprietary form factor, but budget lovers can try their luck with third-party sticks by building their own Fusion Drive or using the SSD separately. Only with the iMac, this is not so easy to do, unlike the Mac mini.
The Marvell controller is paired with SanDisk Flash memory chips. Judging by the marking 05131 016G, this is eX2 ABL MLC NAND memory, manufactured using the 19 nm process technology. Its distinguishing feature is that some of the cells operate in pseudo-SLC mode and serve as a cache, which speeds up write operations and at the same time extends the life of the chip by defragmenting requests. However, there are hardly many such cells here, since the standard volume of about 7% is reserved in the drive (the difference between the number of 128 GB in binary and decimal terms), which is also used for garbage collection, replacing failed cells and other utility functions.
There are eight cases on both sides of the board, each containing two 64Gb (8GB) NAND devices. Thus, not only are all eight channels of the controller filled in the drive, but the interleaving of NAND devices is also involved.
In general, very worthy components for SSD. But we'll leave the verdict until the end of the tests, because in the case of Marvell controllers, a lot depends on the firmware. Previously, we most often saw them in Plextor drives with expertly crafted firmware. Let's see how SanDisk performs.
The iMac's 21.5" hard drive is a banal 2.5" HGST Travelstar 5K1000 drive with a 5400 rpm spindle speed. There is nothing special here.
HGST Travelstar 5K1000 1TB (HTS541010A9E662), photo iFixit
⇡ CoreStorage is the basis of Fusion Drive
The implementation of Fusion Drive became possible due to the fact that, starting with version 10.7 (Lion), OS X has a built-in CoreStorage, a volume manager, which is a software layer between the file system and the drive. Thanks to him, it became possible to redistribute data blocks between two physically separate devices that make up an array, absolutely transparent to the overlying software stack. In CoreStorage terminology, physical devices are called Physical Volumes and can be connected in a Logical Volume Group that has a contiguous address space. It remains only to deploy on top of this Logical Volume, which is presented to the OS as a regular volume. Then the software that manages the migration of data between echelons is included in the case.
Attentive readers may notice that there is another entity in the schema called the Logical Volume Family, which is the container for the Logical Volume. The logical volumes enclosed inside the LVF inherit its properties, the only one of which so far can be full disk encryption - due to this, the FileVault 2 service built into OS X works.
If desired, the design can be disassembled with commands from the "Terminal", booting into OS recovery mode or from an external drive, and then using the SSD and HDD as separate drives. On a Mac with a Fusion Drive, Windows is also installed without problems in the Boot Camp partition. The latter is cut from the end of the logical volume and may include almost the entire address space of the hard drive, but does not apply to the SSD. The Windows installation program, as well as the installed OS itself subsequently, sees the Mac partitions, which leaves the opportunity to accidentally kill all the contents of the Fusion Drive. The next time you install OS X from scratch, Disk Utility, having found familiar hardware, will offer to collect everything as it was with the complete destruction of data.
⇡ How it works
Since in the case of Fusion Drive we are not dealing with cached, but echeloned storage, the first question is where the data written to the logical volume initially goes. It turned out that as long as the capacity of the SSD is enough, it is exclusively used for recording. Using Dynamo, the backend component of the Iometer test utility, a file of over 128 GB was created on disk, and in the process, disk usage was recorded using iostat . At first, only the SSD was accessed, but as soon as the file size became larger than the SSD capacity minus the installed OS, the load was completely switched to the hard drive.
Immediately after the write ended, the fs_usage command showed a barrage of CoreStorage calls, from which RdChunksCS and RdMigrCS start migrating data between array echelons. The fourth column of the listing also shows that the data is moved in chunks of 128-512 KB. Thus, due to the large scale of the moves, a side effect is data defragmentation. If you sum up the calls, you get a volume in the region of 4 GB. Subsequent attempts to write showed that each time the first 4 GB of the file gets to the SSD, and then CoreStorage evicts the same amount of some other blocks to the hard drive. That is, the SSD always has a reserve of 4 GB, which ensures the recording of freshly received data at high speed.
The average sequential read and write speeds of 256 KB blocks with a queue of four commands with SSD are 754 and 391 MB / s (binary), respectively. Very worthy - despite the fact that operations occur on top of the file system. Read / write speed on HDD - 82-88 MB / s.
But how to cause data migration in the opposite direction - from HDD to SSD? This turned out to be quite easy to do with entire files. In order to immediately get into the hard disk address space, the SSD was full during a long write of a large file, and at the same time, a 2 GB file with randomized contents from /dev/zero was created using dd. After the recording stopped, a migration immediately followed, clearing 4 GB of space on the SSD.
The first read of the file passed at a speed of 87 MB / s (most of the load is registered on the HDD). But the second time, the file was already read exclusively from the SSD at 427 MB/s (purge guaranteed to clear the cache first). However, it is easy to see that the speed is far from the maximum: the file ended up on the SSD in a fragmented state.
Further experiments showed that Fusion Drive can also transfer individual pieces of large files. From the middle of a 400 GB file, which due to its size was mostly located on the HDD, a range of 2 GB blocks was read. Two looped read passes of 30 seconds cause some of the blocks to move to the SSD and a sharp increase in overall performance. But in order for all the blocks to be on the SSD, and the read speed to reach its maximum, it took as many as 34 passes! Interestingly, this method worked for writing data to the same range as well. In the latter case, the peak speed was reached on the 15th pass.
Red - reading from SSD (disk0), blue - mainly from HDD (disk1). Green - block migration after read iteration
It turns out that the algorithms by which Fusion Drive selects data for migration operate both at the file and at the block level. And the files have priority. Accessing favorite blocks within files is considered unusual by CoreStorage and requires a long wait for these blocks to be promoted. Well, the iMac is not the best candidate for a database server, and the preference for whole files tends to result in less fragmentation.
In the next step, we will test the Fusion Drive SSD separately and compare it to other high performance PCIe or SATA 6Gb/s SSDs.
The release of the updated iMac was also marked by the appearance of such an interesting thing as the Fusion Drive. This technology is designed to solve an actual problem, which can be described as "I want SSD speed and HDD capacity and without bread, please." So what is this technology?
At the hardware level, Fusion Drive is two separate drives, one of which is a solid state drive (SSD), and the second drive is a familiar hard disk drive (HDD). Apple decided to include Fusion Drive variants with 128 GB SSD capacity and 1 TB and 3 TB HDD variations in their products. Simply put, all the magic of Fusion Drive is carried out at the operating system level and consists in monitoring the frequency of access to certain applications and data and transferring them in accordance with this frequency to an SSD or HDD drive.
Even simpler: the OS and everything that you often run, listen to and watch (a browser, for example) will be stored on a fast SSD, and the rest on the HDD. If you suddenly start learning Photoshop and start running it daily, then this application, as well as the data associated with it (your art), will also be transferred to the SSD.
Fusion Drive is not caching
To be more precise, the Fusion Drive concept does not provide for the data from the HDD to be duplicated on the SSD. The SSD here does not act as a place solely for fast processing, inaccessible to data storage. Here the user gets all the usable space from both drives, that is, if you have a 128 GB SSD and 1 TB HDD, then you have 1.12 TB of available disk space for storing data.
Fusion Drive is not a RAID
As mentioned above, the work of Fusion Drive is carried out at the operating system level. Disk Utility recognizes 2 separate disks, and the OS converts them into a single space.
How to deal with backups
Backups should be done as before. Time Machine will back up as if you had only one drive. In the event of the death of one of the disks, whether it be SSD or HDD, the user will have to do a full recovery. However, if there is no backup, then the user will most likely be able to extract data from a live disk, at least this will be almost 100% likely to be done using additional utilities.
How to deal with replacement
Apple noted that the HDD and SSD in their product are structurally the same as drives from other manufacturers, so if one of the drives is burned out, you can replace it with a third-party drive.
Recording features
The big plus in terms of speed is that all write data is initially written to the SSD, and we know that everything is written faster on the SSD. Naturally, in the future, the OS will determine how often you access the recorded data and decide whether to leave it on a fast SSD, or transfer it to the HDD.
Questions
A lot of questions remain about this shuffling of data from SSD and HDD. How correctly will the OS be able to determine which data should be transferred to the HDD, and which should be left on the SSD? What will such a system give to users who shovel tons of data in transit form and at the same time do not store downloaded information for a long time (downloaded five FullHD films, watched, demolished films, downloaded, watched, demolished, and so on)? Will the extra write and read cycles from a hardware point of view when shuffling data between disks affect the life of the disks themselves (especially critical for SSDs)? How will background shuffling of data between disks affect system performance at the time of data transfer? We hope that Apple has taken into account everything.
