Slashdot Mirror
A Hybrid Approach For SSD Speed From Your 2TB HDD
Claave writes "bit-tech.net reports that SilverStone has announced a device that daisy-chains an SSD with a hard disk, with the aim of providing SSD speeds plus loads of storage space. The SilverStone HDDBoost is a hard disk caddy with an integrated storage controller, and is an easy upgrade for your PC. The device copies the 'front-end' of your hard disk to the SSD, and tells your OS to prefer the SSD when possible. SSD speeds for a 2TB storage device? Yep, sounds good to me!"
This seems like a lot of money to spend for potentially not a lot of speed. Generally, 2.5" hard drives aren't quite as fast as their 3.5" counterparts anyways, so you're spending a fair bit of money to speed up something that wasn't really made for speed anyways.
Sure, you can "drop it right in" to your existing computer, assuming that your desktop is for some reason already using 2.5" SATA drives. And if your desktop is currently using 2.5" SATA drives you probably didn't build it to be a speed demon anyways.
Damn_registrars has no butt-hole. Damn_registrars has no use for a butt-hole.
Haven't disk manufacturers been doing this forever, using faster memories to cache disk? I guess the difference now is that the memory is slower than DRAM and non-volatile so it isn't lost in the event of power failure? Or maybe you can get more flash storage at a low price point?
-- Erich
Slashdot reader since 1997
How would the disk supposedly know, which part of the 2TB I am going to need next?
The device takes the form of a 2.5in to 3.5in hard disk caddy with a couple of SATA connectors on the end.
Good job Claave! You apparently didn't even get to the second paragraph before submitting the article. You can't use a 2TB hard drive with this because there are no 2TB 2.5" drives yet.
This guy's the limit!
No software or driver update is required
Some software is needed to achieve the magic
ZFS? Hybrid storage pools have been around for a long while, and exist as a pretty well balanced software solution to this problem. Hybrid solid-state/magnetic disks were in the market as well which used a similar technique. There is nothing new or impressive about this device.
This adapter is for 2.5" hard drives - if you put a 3.5 drive in it, you wouldn't fit drive+adapter+SSD into a 3.5" bay. Who makes a 2TB 2.5" SATA drive currently? I am not aware of any...
Damn_registrars has no butt-hole. Damn_registrars has no use for a butt-hole.
Well... it looks like there finally might be a reason to spend the money on an SSD. Up until now, it would be a nice speed boost, but the cost:performance ratio is so out of whack for SSDs, it just makes purchasing one ridiculous unless you have some very specific needs. For 95% of the people who have purchased them, they just want the biggest e-peen. That's fine and all, but my days of swinging around the biggest e-peen are over, so I've held off buying an SSD until the prices drop and capacity goes WAYYYY up.
However, with this particular device, it actually makes it worth it to spring for a lower capacity, fast SSD (for naturally less money than the higher capacity ones) that will cache the files I use the most. The question is, and it wasn't really clear from the article unfortunately, is it a real time "mirror" - in so far as over time, if I start using more file and others less, will the drive start caching those newer files that I use more than the older ones I am using less? Assuming it does (since it would be kind of useless if not), this makes an 80 GB SSD a viable option!
However, the one drawback I see to this is my current RAID 0 setup would be unusable and I'd have to switch back to using one drive. That's not a terrible thing, as I've never been too thrilled with the whole RAID 0 thing and if the minor speed advantages it imparts are fully mitigated by the SSD - switching over to a single 2TB drive is awesome.
I would definitely shell out some bucks for this solution, assuming it works as advertised.
I DNRTFA, but this really just seems like a fancy version of cache to me....
This thing uses 3.5" drives, or you could slap it onto a 2.5" drive if you wanted to. The thing TAKES THE FORM OF a drive caddy - it is not a drive caddy.
Eloi are stupid, throw morlocks at them!
This thing uses 3.5" drives, or you could slap it onto a 2.5" drive if you wanted to. The thing TAKES THE FORM OF a drive caddy - it is not a drive caddy.
Actually, after looking at it more, it is a drive caddy -- for a 2.5" SSD. This device basically acts as a daisy chain controller that you hook both a 2.5" SSD and a regular 3.5" HD to. The controller then presents the combined device to the BIOS/OS as a single drive.
This guy's the limit!
In order to appear as one storage device in Windows, SilverStone has needed to use some software to...
There is the turn off for me. If I were to use something like this I would want an OS agnostic solution. Of course that would mean the caching would have to be done at the block level rather than the file level so it might not be able to be as bright (a block level cache manager wouldn't know to deallocate space on the SSD immediately when a file is deleted for instance), but it should be quite practical to design an algorithm that keeps the most often used blocks in the cache (the SSD) without the whole thing being needless wiped first time you copy a massive data file in (you wouldn't want that 20Gb file to be written to the SSD first time it is laid down, at the expense of dropping blocks frmo OS startup files and such, in case it is hardly ever accessed again - for instance an image of a blueray disc that you are copying to another disc would not want to touch the cache as it'll probably be written one, read once then wiped. How this block-based cache management algorithm would work in detail is left as an exercise for the reader...
This stuff all needs to be within the same hard drive.
Sell a 2TB 3.5" hard drive with a 64GB *fast* SSD cache on board (transparent to the OS), and then we will be talking.
Now, maybe you could do it safely if the device had RRD ram to handle the caching, SSD flash ram to handle power outages, a rechargable battery or ultra cap to provide power to write the RRD ram to flash ram after a power outage, and a controller to handle all this. You would need to implement all the normal os buffer caching and writebacks as well.
I suspect we may have read different articles. Your assertion of
You mount the fucking 2.5" drive in the caddy and mount your 3.5" HD where you would normally mount it
Does not match the article when it says
The device takes the form of a 2.5in to 3.5in hard disk caddy
So I thank you for your kind concern of
un a fucking cable from your HD to the caddy. Is this so fucking hard to get a grasp on? For christs sake
And I hope you have a very nice day kind sir.
Damn_registrars has no butt-hole. Damn_registrars has no use for a butt-hole.
Come back when there are some benchmarks to look at.
There was a paper some years ago about building the file system in such a manner that smaller files were placed on an SSD ( 1 MB) and large files were placed on a harddisk. At that time, SSDs were a lot smaller than today though.
Generally, it can make sense to discriminate your files because they don't all have the same space and access characteristics. Maybe 100 files is taking up 90% of the space compared to the other 9900 files. Maybe it's similar for the access pattern.
Still, for the idea to fly, you need to a robust algorithm and it needs to be clever about the strengths of the hardware. For instance, SSDs aren't so hot at random writes, sadly. Less than 0.1 msec write time would be neat for an ACID database.
This solution uses two 3.5 inch drive bays in your computer, one for your large platter drive, the other for the caddy with a SSD drive.
Some software is installed (Windows only) that makes the two drives look like one.
The most used files from the large drive are copies to the smaller SSD drive. When files cached on the SSD drive are requested, they are read from there, if they do not exist there the request is passed onto the bigger drive. If the file is being used enough it will be copied to the SSD drive at the same time as the information is getting sent to the computer. You will not get SSD drive speeds in this case.
Yes, this is just using a SSD drive as a cache.
The product does not come with SSD storage, you have to buy a SSD drive of your choosing as well as this caddy.
Microsoft, Apple, Google, Amazon what's the difference? All steal money from devs and control with walled gardens.
It seems to me that the natural evolution in hard drives would be to build the flash cache on to the controller board on the hard drive. Is any drive manufacturer building this kind of hybrid flash/magnetic drive?
They even have a fucking picture.
The 2.5 caddy is for your SSD. Mount your 3.5 wherever you like.
Weaselmancer
rediculous.
This seems like something a good operating system can implement with relative ease without even needing a custom tailored filesystem to do so.
"A good operating system" isn't compatible with thousands of proprietary third-party apps and device drivers designed for the majority operating system for home PCs. Nor can the data on a drive set up for use with "a good operating system" easily be transplanted into another PC whose operating system is not aware of the look-aside SSD cache.
1- RAM systems work that way too: L1 cache, L2 cache, slow RAM, to compare to RAM cache (OS or controller), SSD, HD.
2- SSDs right now are very un-optimized: you've got to put, for example, your whole OS on them, even though I'd guess 20-30% of the files are actually read frequently enough to justify being on the SSD... and probably 5-10% of the files are *written* frequently enough to justify NOT being on the SSD. So seeing the SSDs as a cache rather than a hard disk makes a whole lot of sense, and probably doubles or triples their efficiency, by letting them hold only files that best fit the SSD strong points, and hence a lot more of those files.
My concern is that this "cache"- or "ready-boost"-like mechanism requires quite some intelligence, either, at the most basic level, to keep count of which sectors get read a lot and written not so much, or even, at a higher level, to identify usage patterns and cache the appropriate files (boot, app launch, game play). I'm not sure where that intelligence goes on with the product described... if it goes on at all.
The Cloud - because you don't care if your apps and data are up in the air.
There is nothing new or impressive about this device.
Other than that it is compatible with applications and peripheral drivers designed to run on the majority operating system for home and office PCs, which has no support for ZFS.
Good Grief, Alice! They've invented cache!
I'm a Programmer. That's one level above Software Engineer and one level below Engineer.
"'front-end' of your hard disk"?
What does that even mean?
Performance of disk systems is determined by the cache system almost entirely (er... given same data transport, etc).
Usually the write side is more complex because you don't want your device telling the o/s that the write committed when it is still in vulnerable cache. Storage system mfrs recognize this and put in batteries to make sure the write side cache is able to survive power outages. This adds weight as well as complexity and there is always residual risk in these systems.
If you can make a non-volatile cache write that is effectively equivalent to writing to the magnetic media and do it without external support (eg batteries) then you have a better device.
Also, this has the potential of bringing high performance writes to the disk device level instead of the storage chassis/system.
Opensolaris can use SSD as cache device for zfs volumes. More details here http://www.filibeto.org/~aduritz/truetrue/solaris10/zfs/zfs-what-next-sdc09.pdf
Microsoft has a concept they call readydrive for this, mostly for laptops. It was released with vista (Not in XP and I never heard anything about Linux support) and seems to have kinda died. Last I heard anything about hardware was in 2007 with releases from the usual names (Samsung, Seagate, etc.), and I saw a few reviews (which appeared rather underwhelming (supposedly due to poor drivers), which resulted in a blame game between Microsoft and the manufactures over who's fault that was), but I don't think I ever saw the devices for sale.
There's also plans to include this type of functionality in the ATA-8 spec.
upon the advice of my lawyer, i have no sig at this time
I'd rather it not. That way when I upgrade the hard drive, I can toss the old HD and keep the more expensive SSD part.
From http://www.silverstonetek.com/qa/qa_contents.php?pno=HDDBOOST&area=usa
After the initial mirroring of data is completed, SSD and HDD will have the same front -end data. HDDBOOST's controller chip will then set data read priority to SSD to take advantage of SSD's much faster read speed. HDDBOOST's priority will be determined by the following rules:
1.When data is present on both drives, read from SSD.
2.When data is not present on both drives, read from HDD.
3.Data will only be written to HDD.
[...]
In normal operating system environment, a system drive gets written onto constantly until the system is turned off. Compared to using SSD only as the main system drive, HDDBOOST will only write to SSD once sequentially during system boot up when it activates mirror backup. This significantly reduces the wear and tear that normally occurs when writing data to SSD.
This makes no sense. How is it supposed to read from the SSD if the SSD doesn't have a current copy of the data because you only wrote it to the hard disk?
Moderating "-1, Disagree" is simple censorship. Have the guts to post your opinion.
the majority operating system
ReadyDrive
As of last month, Windows XP still held two-thirds of market share; Windows Vista and Windows 7 combined made up about one-fourth. Of these, compro01 pointed out that ReadyDrive requires Windows Vista or higher.
You know, you don't need a sig that announces "Slashdot reader since 1997". We can all see the number beside you nickname.
Sounds a lot like the CacheCard from SiliconDust for Series1 TiVos, except instead of an SDRAM DIMM it uses an SSD. And the CacheCard doesn't sit between the devices but instead connects to the TiVo motherboard's card-edge connector, provides an Ethernet port, and is designed only to cache a particular 0.5 GiB part of the drive.
But since the SDRAM loses its contents on power off, it does add significant time to test and fill at startup, while the SSD would be ready nearly immediately.
Oh, say does that Star-Spangled Banner entwine / The myrtle of Venus with Bacchus's vine?
I am not sure about the speed advantage of reads from disk, given the problem of what to prioritize; but I could see the advantage of writes to disk.
Does that make any sense?
Living in Chile
You'd be better off just buying a second drive and doing a RAID 1.
Why hasn't someone already made this, just like caching IDE controllers? (Terminology wrong, of course, in that SATA doesn't need a "controller" in the IDE sense because it's host-to-host)
An inline device that you plug in the SATA line. Should be the size of a USB memory stick with a connector at each end, or with an extension cord & connector at one end. Give it 2 to 8 GB of memory, again like a USB memory stick. Different sizes could be different price points.
Monitor all reads. Cache them while you have empty pages. Obviously the first thing to be read and cached will be the boot sequence on the first powerup after installation, which is probably what you want most anyway, and 2GB is bigger than your core working set even on Windows. On any read, if in cache, return cached copy (obviously), otherwise pass along to disk. Best design will completely avoid delay on the return data by letting it pass through and monitoring it multidrop. Maintain a reference counter on the N pages cached, and on the next favorite N pages (at least); any time a page in cache (or reference count list) is written, invalidate it, replacing the next time you see one of your "next favorite" pages go past. Ditto if a "next favorite" reference count gets higher than the lowest of the N live pages.
Remember, this thing never instigates action on its own, just piggybacks on system activity. Eventually it stabilizes on your OS, your most-used programs, etc. When you do an update, things get invalidated for a while - your next-frequently-used replace them, until the reference counts go back up. It's self-tuning. The operating system doesn't even know it's there - no driver, no changes, no special code. The disk drive doesn't know it's there. For a frame delay on the SATA request you get acceleration on everything; and if you parse the request in parallel to match you can keep the delay below a full frame.
I think that a 32GB SSD in this role would be sufficient for a fairly big boost in performance. I do think that it would be okay to have a 3.5" HDD embed the SSD portion in a similar fashion that this device does, with a 16-32GB SSD and a 16-32MB ram cache on top. As to the more expensive SSD part, well currently pricing has been dropping rather quickly, and would expect to see similar gains for the next couple years.
Michael J. Ryan - tracker1.info
There are alignment tricks with SSD around their large erase blocks, so you have to be careful partitioning.
Also, consumer-grade MHC SSDs are _not_ tremendously faster than spinning disks in transfer speed. Maybe 20%. Access time is where SSDs shine, 0.2 ms vs 8-10ms .
A simple scheme I use is to put the OS & small, frequent datafiles on SSD, and large [image] files on platter.
This might not help large databases with sparse access, but lots of RAM disk cache should be better. IIRC Seagate had a disk with flash boost, but had trouble with it.
For a really wide range of applications, what you really need is fast caching of writes to stable storage, so your database transaction logs, file system journals, and modified inodes are saved and the application can go on to its next steps while the SSD box copies itself to higher-latency cheaper rotating machinery. Read-caching is something the operating system can do for itself in RAM (though the SSD box can also do its own prediction, especially for things like track-at-a-time reads of the disk), and the SSD can often keep a bigger read cache than the OS can because it's less performance-critical than caching in system RAM.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
Yeah, it's a disk cache that's external to your system RAM, with a (hopefully) no-brainer setup. You can use whatever size SSD you want, so it can be bigger than you'll get by expanding your system RAM or replacing your motherboard with one that handles more RAM, and you can use slower RAM or flash for the SSD as opposed to blazing-fast system RAM.
The big performance win you get from systems like this is write caching on database transaction logs and file system journals, because the writes don't have to wait for rotating machinery to spin around and seek to the right part of the disk, and you can queue stuff on stable storage outside the OS so the application can go on to the next step instead of waiting around for disk interrupts.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
In 2007 there was a whole movement toward hybrid drives -- it went nowhere.
The problem with quotes on the internet, is that nobody bothers to check their veracity. -- Abraham Lincoln
Haven't disk manufacturers been doing this forever, using faster memories to cache disk?
Digital's ESE series disks. RAM backed by disk with (iirc) write-behind caching. Expensive (memory was, after all) but in production in the 1980's. Welcome to the future.
Do not mock my vision of impractical footwear
Windows ReadyBoost already does this. Plug-in an SSD, turn it on, and it caches frequently accessed files there. The last benchmark I read on it said it wasn't any faster though - probably because USB flash-drive SSDs are really slow since they are optimized for physical size, data density, and power consumption -- not speed.
Linux do this in software?
But then I was dumb enough to buy DELL: http://www.tomshardware.co.uk/forum/254961-14-warning-careful-ordering-dell-machines-ssds
OK let's suppose you have a fairly vanilla Linux desktop system, with one spinning hard disk and one SSD. How do you set things up in software to use the SSD as a kind of cache for the hard disk?
-- Ed Avis ed@membled.com
This is kinda like my Vertex SSD boot drive and two 1TB HD raid 1 bulk data setup. Only slower...
Yest I am posting this reply - to my own reply - just to egg you on. You probably don't have any mod points left or you would have tagged some of my other posts with "flamebait" as well.
Your attempt to knock me down failed. Indeed it failed miserably as my karma remains at excellent. You really should have found a better way to use your mod points then following every post I made in this discussion with "flamebait". Even better yet would have been for you to actually voice your opposition with a reply, but apparently that was above you.
In the end, your efforts were for naught. If you ever get mod points again perhaps you will use your points more wisely. Currently I am laughing in your general direction.
Damn_registrars has no butt-hole. Damn_registrars has no use for a butt-hole.