Are SSD Accelerators Any Good?

MrSeb writes "When solid-state drives first broke into the consumer market, there were those who predicted the new storage format would supplant hard drives in a matter of years thanks to radically improved performance. In reality, the shift from hard drives (HDDs) to SSDs has thus far been confined to the upper end of the PC market. For cost-conscious buyers and OEMs, the higher performance they offer is still too expensive and the total capacity is insufficient. SSD cache drives have emerged as a means of addressing this situation. They are small, typically containing between 20-60GB of NAND flash and are paired with a standard hard drive. Once installed, drivers monitor which applications and files are accessed most often, then cache those files on the SSD. It can take the software 1-2 runs to start caching data, but once this process is complete, future access and boot times are significantly enhanced. This article compares the effect of SSD cache solutions — Intel Smart Response Technology, and Nvelo Dataplex — on the performance of a VelociRaptor, and a slow WD Caviar drive. The results are surprisingly positive."

Comments

bcache

[Anonymous Coward]

For Linux users: http://bcache.evilpiepirate.org/

Lets you use any SSD as a cache in front of another filesystem.

Re:bcache

[drinkypoo]

Lets you use any SSD as a cache in front of another filesystem.

It would be niftier if it would let you use it as a block cache in front of any filesystem, instead of just one located on a specially-prepared partition. dm-cache will do this but isn't up to date.

Re:bcache

[mitgib]

Lets you use any SSD as a cache in front of another filesystem.

It would be niftier if it would let you use it as a block cache in front of any filesystem, instead of just one located on a specially-prepared partition. dm-cache will do this but isn't up to date.

Maybe Flashcache would be a better choice for some. I use this as a read-cache on several VPS nodes and the results are impressive.

Re:bcache

[antifoidulus]

Flashcache is a block-level caching algorithm, which means that it will work with any device, but it takes a metric TON of memory as it has to retain cache info for every block on the device. If you have the memory then yeah, you can get some speedup from it, but if you are memory constrained eating up that much memory for the small performance boost isn't worth it.

Re:bcache

[Anonymous Coward]

For Linux users: http://bcache.evilpiepirate.org/

Lets you use any SSD as a cache in front of another filesystem.

For ZFS users:
* read cache: zpool add {pool} cache {device}
* write cache: zpool add {pool} log {device}

Re:bcache

[Gaygirlie]

That's what I use on my laptop: I've got a 16GB class10 SDHC-card formatted as NTFS and fully dedicated to ReadyBoost and I do notice some speed-up in boot and firing up applications. Nothing spectacular and obviously an SSD would be ideal, but it is still better than nothing, especially with the prices SDHC-cards go for nowadays.

Re:bcache

[Nimey]

Likewise I'm using a 16GB USB3 stick for Readyboost. It's certainly speeding up Saints Row the Third's otherwise atrocious loading times: something like 5 seconds to load my campaign versus a minute or so without.

Re:bcache

[ShoulderOfOrion]

Why bother? I have an HDD mounted as /, and an SSD mounted as /usr on my Gentoo system. Using atop I consistently see the HDD receive 10-20 times the writes the SSD receives but only about 2x the reads. In other words, on Linux the SSD is already serving primarily as a read-only caching filesystem just by mounting it correctly.

Re:bcache

[ToasterMonkey]

For Linux users: http://bcache.evilpiepirate.org/

Lets you use any SSD as a cache in front of another filesystem.

Solaris and Windows have been shipping with production ready L2 FS cache for years already, L2ARC/ReadyBoost. I'll give Apple a pass because their systems are mostly not designed for adding drives, and they were apparently betting on high capacity SSDs coming down in price by now. Desktops have less of a need for caches in the tens of GB anyway. Linux, as a server OS doesn't have much of a good excuse, why wasn't L2 cache worked out years ago when everyone was racing for TRIM support? Using smaller cheaper SSD drives as L2 cache almost makes too much sense. It covers up the short write cycle lifetime and poor sequential read performance. 60 some odd GB of cache starts to look pretty dang good for a lot of server workloads.

I feel I should point this out because these cheesy Linux +1 MeToo posts are _really_ aggravating to people who use it professionally. It's a tool. We're not in love with it.

http://arstechnica.com/civis/viewtopic.php?f=21&t=1114013
The developer apparently didn't even know what the ARC algorithm is... which is just bizarre, like developing a race car without knowing what variable valve timing is. Not saying it is needed, but what level of quality do you expect out of this?

Re:bcache

[terminal.dk]

You should not expect much speedup from using a 10Mbyte/s memory card in front of a standard 150 MByte/s sustained transfer drive.

If the small files are stored in your cache, you might save some seek time. But you can't compare some ultra-slow USB / SDHC card to a 2-300 Mbyte/s SSD.

I tried the SDHC, did not work well. A fast USB 3.0 stick in a USB 2.0 port was way better, but still does not compare to SSD.

Re:bcache

[Gaygirlie]

You should not expect much speedup from using a 10Mbyte/s memory card in front of a standard 150 MByte/s sustained transfer drive.

You said it yourself: "sustained." The whole point with ReadyBoost is that it uses these Flash-devices for matters where low latency is more important, sustained transfer-rate is therefore not important. It doesn't even try to cache multi-megabyte files, it caches small files and details that are accessed frequently: a regular HDD is quite bad at reading dozens of small files from all over the disk due to seek times.

If the small files are stored in your cache, you might save some seek time. But you can't compare some ultra-slow USB / SDHC card to a 2-300 Mbyte/s SSD.

That's what I said.

I tried the SDHC, did not work well. A fast USB 3.0 stick in a USB 2.0 port was way better, but still does not compare to SSD.

If you were expecting SSD-level performance then you clearly didn't understand fully what you were doing in the first place. It is not meant to replace an SSD, it is simply meant to speed up your system as compared to only using a regular HDD.

Re:bcache

[Skal Tura]

USB latency is actually rather high. Infact, rather VERY high.

Absolute minimum latency for a fetch is 16ms on USB port. It seems this has had some work on it, now being 125Hz rate by default, instead of 90.
But still 8ms for sending request for file, device gets it, let's assume it's ultra fast and takes just 3ms to find, fetch and prep reply packet (and assuming fits on 1 packet), it means 16ms has been spent BEFORE the data can be sent back, 24ms for the whole round trip.

HDDs seek faster than this, SO if your HDD is not having other activity, for single fetch your HDD is faster. Unless it's Caviar Green.

Re:bcache

[Skal Tura]

Mac OSX is basicly highly modified FreeBSD/NetBSD, so it might actually already have ZFS support, therefore L2ARC.
Knowing apple tho they have probably disabled it and gives you no means to even try using ZFS.
Besides that they've probably locked down SSD support to few select drives as well.

Linux does not by default have these options but several are available. I bet some vendors do include these supports.
For ZFS you don't need kernel mods in many distros.

Re:bcache

[NighthawkFoo]

Because then you'll waste writes on /tmp and /var.

Re:bcache

[Anonymous Coward]

You'll want /tmp and (depending on installed servers and how your distro is configured) /var on the HDD; if you have enough RAM, /tmp and /var/tmp on a tmpfs and the rest of /var on the HDD. So, / on the SSD, /home and /var on the HDD, and /tmp and /var/tmp either on tmpfs or on the HDD. /usr and /boot as dedicated partitions on the SSD may be a good idea too, all with sane defaults (for example, /boot should be mounted only when you update the kernel, / can be read-only and remounted in place when doing your weekly updates, etc).

Re:bcache

[ThatOtherGuy435]

OS X had an experimental/development version of a ZFS kernel module that could be enabled from CLI in... I think 10.4 or .5. Since then, it was depreciated and removed, leaving no current ZFS support.

Re:bcache

[karnal]

While I don't know the technical details as much, readyboost does help in some situations - so there's got to be something else happening on a hard drive that is even higher latency than what you're describing about one link in the chain of USB. I have an older 4gb CF card in my machine at home - no other use, so I cranked it into a readyboost drive. It can peak out USB sustained speeds (it's a UDMA5 capable drive) and I do have it going through a USB controller, but once the OS is loaded things are just snappy overall. My main HDD is a raptor, so it's about as fast as you'll get on a consumer level HDD from a seek perspective.

No.

[Anonymous Coward]

Hybrid drives or mixed mode setups kinda suck ass now that actual ss drives are getting to a reasonable price/size.

SSD for os/programs.

Giant TB+ drive for storage and media files.

Re:No.

[wbr1]

For the average joe, they dont want to have to manage putting os/apps/frequent files on one drive and split the rest elsewhere. Software that automagically does this and keeps the cache up to date is a boon for the non power user.

Re:No.

[artor3]

Bingo. I've been manually managing the shifting of files back and forth between my HDD and SSD for a couple years now, and while it's not particularly hard, it's not something I'd want to guide a non-techie through. Getting the OS on one drive and the user folders (my documents, videos, music, etc.) on the other isn't particularly well documented, and moving individual Steam games seems to require console commands, a rarity in Windows.

Even though I can manage it all myself, I would absolutely switch to having software handle it if there were a reliable, free, easy-to-use option.

Re:No.

[Lumpy]

Odd, the hybrid drive I just bought doesn't suck ass. It in fact is faster than ANY hard drive you can buy that has a 750gb size. Unless "suck ass" is the new hipster slang for "really fast". It made my old out of date quad core i5 laptop a whole lot faster.

Re:No.

[afidel]

I assure you that there are MANY 800 GB SAS/SATA SSD's that can beat your hybrid drive, they just cost more than most people will spend on their entire computer =)

Re:No.

[OzPeter]

Hybrid drives or mixed mode setups kinda suck ass now that actual ss drives are getting to a reasonable price/size.

SSD for os/programs.

Giant TB+ drive for storage and media files.

I have a laptop with a single drive bay you insensitive clod

Re:No.

[Eskarel]

I'm sick of this myth. The math I've done indicates that, presuming that the drive is doing a halfway decent job of spreading the writes around, most cheap SSDs are rated to allow you to write the entire volume of the drive every day for about 30 years. Now personally I don't even come close to doing that, and your average physical HDD is rated for about 5 years, with 10 being a seriously long life.

If you buy a reasonable quality SSD at present your drive will not last long enough to see a significant level of NAND failure and what will kill it will be one of the million things that kills HDDs on a regular basis.

Re:No.

[FlyHelicopters]

^ This

Also, a Quad Core i5 isn't out of date, last time I checked. :)

BTW, a pair of 512GB SSDs are no longer crazy expensive, they can be purchased for less than $1,000 total, which is less than many gamers spend on their computers.

Re:No.

[TheLink]

From what I see nearly all data-loss failures in SSDs are due to bugs or faults and not due to wear.

Re:No.

[DigiShaman]

SSDs have a propensity to just die like a normal HDD. Not sure why. Could be overheating, poor quality in materials making the ICs, buggy code in the firmware someplace. Who knows. But I've seen plenty OEM Samsung and OCZ Vertex 2 drives go tits up in a nanosecond. Either you can't read the data of the drives, or flat out wont enumerate SATA side (effectively bricked).

So why SSDs look great on paper in "theory", real-world stats say otherwise above and beyond just my own experiences.

OTOH, like the SSD crackwhore bitch that I am; once I tasted the speed of SSDs, I'll never go back. I just schedule daily backups to a standard HDD. Windows 7 Backup or Apple Time Machine for you Mac heads.

Re:No.

[DigiShaman]

Standard desktop chipsets can get real flaky with 16GB of RAM and above. So be sure you get a single Quad kit and not 2x Dual kits like most people get (because it's cheaper). But then again, if you're serious about needing that much RAM, I suggest going workstation level with an Intel Xeon or AMD chip. Those are the only to line of CPUs that will support ECC. Last thing you want to have to worry about is some bit flips happening someplace and then the corruption being committed back to disk. Ugh!!! The though alone is enough to give me ulcers. Seriously, go with ECC when working with that much memory.

Re:No.

[Sir_Sri]

That was true back when you were talking about MB numbers. It's definitely not true when talking in that rage of GB.

To use windows as an example, it will try and cache what it thinks you're going to load based on I think a fairly simple algorithm. Which means it's usually wrong. If you never access more than 32 GB worth of data from your HDD then sure, 32 GB of Ram will do the trick. But, for example, if you play WoW or SWTOR (both of which flutter around 20GB), any other game + web browser + windows you could fairly easily waltz past 32 GB of data, at which point you're into 'cache misses'. And yes, this is conceptually the exact same problem as cache hit ratios, just working at a different level (logical files or directories rather than lines of memory).

I had virtually no performance increase going from 12 to 24 GB of RAM on general disk use.

You can get a big boost from an SSD, and especially, getting something that will actually work a SATAIII connection at full speed. My x58 board is lucky to pull more than 200MB/s from even a very good SSD, whereas the same drive on a sandy bridge board will do 450-550 range.

Now keep in mind, a regular HDD is about 70MB/s for sustained data. Put that in a raid 1 (mobo hardware, or software) and you can see 120-130, so an SSD on a bad connection may not be that much better than much less expensive RAID.

Re:No.

[Anonymous Coward]

I used Windows 7 Audit Mode to install the users folder and programdata onto a HDD and pointed the temp folders to also to run from there.
I put the page file onto another HDD that only plays media files.
Then Steam was installed to the SSD but then the main steamapps folder is symlinked back to the HDD with the users folder.
Since I hate loading times in Skyrim (especially with stacks of mods) I copied those to the SSD and symlinked them back (Symlink inside a Symlink lol).

Setup works wonderfully well, Steam starts up really fast while keeping a lot of space free on the SSD for other applications.

Complete Setup:

1x Intel 520 128GB SSD
2x WD RE4 2TB in RAID 1 (Users, Programdata, Temp and most steam data)
2x Seagate 1TB in RAID 1 (Media, Page File)

Re:No.

[tlhIngan]

Now keep in mind, a regular HDD is about 70MB/s for sustained data. Put that in a raid 1 (mobo hardware, or software) and you can see 120-130, so an SSD on a bad connection may not be that much better than much less expensive RAID.

You're ignoring a very important fact.

An SSD is at least an order of magnitude faster still because the seek time is in the microsecond range. So even an SSD on a bad interface can easily peg the interface for random I/O, while the super RAID array doing the same accesses can bog down to a halt.

The reason? Seek times. A typical hard drive is around 7ms or so, which means if you're doing lots of seeks, you'll never get that sustained transfer rate. Worst case, you can easily get less than 1MB/sec if the hard drive is reading 4kB blocks at random locations.

A hard drive is great for long reads and writes. An SSD excels at random I/O and OS/application usage tends to be random I/O. It just makes the whole system feel "snappier" purely because read requets are fulfilled immediately versus skittering the head over the platters.

In fact, Windows 7 does a quick test to determine if it's running on an SSD - it does a bunch of random I/O. If the drive is capable of more than 50MB/sec, it's an SSD because no spinning rust can meet that requirement due to seek time.

Re:No.

[TheLink]

Seems to me the current hybrid drives don't do write-caching, they only do read-caching.

I can see why read-caching would be a lot simpler to implement, but I bet decent write-caching will really make hybrid drives as fast as SSDs for most desktop use.

Copying files from one location to another at SSD speeds till the write-cache fills up. Then while you do something else the drive flushes the cache to disk.

Re:No.

[isorox]

I'm well aware of seek times. And honestly, they don't matter all that much. For a very small file they take you from 1-2 seconds to effectively instant yes, but for a significant file you're throughput limiting yourself anyway.

The problem comes when you try to read a small file while reading the large file. If you want to preview 1,000 files (say thumbnails for a directory full of pictures), that's 1000 reads. At 10ms each (hdd), that's 10 seconds. At 10ns each (ssd), that's 10ms.

Sure, keep your read-only media on a large hard drive, as you'll tend to be pulling it off as a single stream, with only one open file, but keep the majority of your files on an SSD.

Re:No.

[Dot.Com.CEO]

The Windows algorithm is anything but simple. It's actually quite damn good, and the system is measurably faster while using Readyboost.

Re:No.

[SpinyNorman]

Not just for power users ...

In Linux it's simple enough to, say, mount your root (OS data) folder on an SSD and /home (user data) on a HDD, but Windows 7 isn't so flexible.

What most people (power users) end up doing under Windows 7 is to install the OS on an SSD, then use a "junction point" (cf Linux hard link) to redirect the /Users folder to a HDD (and reconfigure the Windows TEMP directory to be on the HDD to avoid killing the SSD with excessive temp file create/delete cycles). The trouble with this is that Windows 7 junction points don't play nice with restore points, as you'll find out when having to revert to a restore point and all your user data disappears requiring major hackery to restore.

So, for Windows 7, a HDD with built in flash cache is a MUCH more convenient solution than using a separate SDD - even for a power user.

Re:No.

[Miamicanes]

> SSDs have a propensity to just die like a normal HDD.

No, normal drives tend to become flaky, then get super-slow, then start to make grinding noises and die outright a short time later. SSDs just commit data-suicide, then go into "panic" mode and lock the entire drive if they sense that you're trying to do data recovery on them. Ask anybody unfortunate enough to own a drive based on the Sandforce SF-1200 controller, like the OCZ Velocity2. OCZ's forums are *littered* with post after post after post (continuing to the present) from people who've had the drive just spontaneously decide to fail.

The problem isn't flash-wear... the problem is a perfect storm of buggy firmware, drive-level encryption, and paranoid firmware that views aggressive attempts to recover data lost due to that buggy firmware as a hacking attempt & locks out the entire drive in a way that can't be fixed by end users (mostly, because Sandforce won't allow the recovery/repair tools to be released to end users). IMHO, it's completely inexcusable. At the VERY least, they should have made the encryption and protection something that can be disabled by end users (probably requiring complete reformatting, but at least present as an option). Then, they could have made a recovery mode that allows drives that had the encryption disabled to just sequentially rip the raw bits from the flash for offline recovery. But no. They have to protect their shit IP that nobody who's been burned by them will EVER purchase again anyway, and casually write off petabytes of lost user data due to their brittle embedded firmware and protection as "not our problem".

OCZ and Sandforce are the best poster children for a class-action lawsuit since the day HP decided to sell CD writers without cache (that their engineers GUARANTEED would turn at least a quarter of the discs they touched into coasters). The sad part is that such a suit could only have things like piddling amounts of money as the penalty, instead of compelling Sandforce to furnish all source, signing keys, and in-house utilities relevant to the SF-1200 to anybody who's ever had the misfortune of purchasing a drive based on it.

No way. Too late. SSDs already cheap enough

[Anonymous Coward]

240GB SSDs are bouncing around 200. 2 bills for the boot SSD and your old drive gets the data partition and you are beating these hybrids on performance AND price.

Re:No way. Too late. SSDs already cheap enough

[shitzu]

This guy is saying - for a $200k i can buy a Ferrari. You are saying - hey, you can get a perfectly good combine harvester for less money.
Hard disk gigabyte price vs SSD gigabyte price is not the issue discussed here - performance is.

Re:No way. Too late. SSDs already cheap enough

[lightknight]

Exactly. I have a 240GB SSD for my laptop and desktop's main drives, with oodles of secondary storage (7200 RPM, of course). The difference is magnificent. If you've never used a SSD before, you simply do not understand -> Adobe Photoshop CS5 loads in only 3 or 4 seconds. Try doing that on a mechanical hard drive, and it's just PAIN.

Re:I have seen SSDs used just to load the OS

[pla]

To me it is not worth it to watch your os boot faster.

First of all, putting the OS on a disk by itself doesn't only mean that Windows runs faster - The OS reads and writes to its files on a near continuous basis. For years before SSDs, we've known that simply getting that activity segregated onto its own disk, away from "real" file activity, gives a decent performance boost across the board; moving it to an ultra-fast random-access media helps even more (and even if you don't care about boot time, how about "responsiveness"? Every time Windows needs to wait for some stupid little icon to load, you need to wait for Windows to wait for some stupid little icon to load).

Second, SSDs have gotten a lot bigger and a lot cheaper. You no longer need to decide between spending a fortune or segregating your apps out; a $60 SSD will hold the OS and every app you could ever possibly run, with plenty of room to spare. Yes, you'll still want that second big-slow-and-cheap HDD for general purpose storage, but you haven't needed to carefully weigh "on which disk should I install this program" for at least a year.


Flash ram is not a permanent solution and will die due to the limited number of writes.

And you think a drive with actual moving parts will live forever?


Make no mistake, SSDs have their flaws, and cost definitely still counts as one of them. But once you really use a system set up with SSD system / HDD data, you'll never even consider going back. And mere boot time has nothing to do with it.

Re:I have seen SSDs used just to load the OS

[cdrudge]

What also is not addressed in the article is the reliability of the SSDs. Flash ram is not a permanent solution and will die due to the limited number of writes. If you use mysql or MS access or run low on space and use XP that thing will be dead in a matter of months. It can only handle so much paging and writes before it dies. Tricks in the firmware move the write bits to random places in memory to prevent this but as it fills up the paging needs to keep to keep hiting the same memory addresses.

There are a variety of different ongoing tests to look at how long drives actually last. Looking at a fairly standard older Intel 320 40GB drive, it went 190TB written before the MWI threshold was reached, and continued on until 685TB. That means it completely rewrote the drive 17500+ times.

No, it won't last forever. And it's not ideally suited for every single industry and use. But for the typical user, they are more likely to need a larger drive or otherwise upgrade then wear out the drive.

All software is not created equal

[Nemilar]

It seems that SSD accelerators can be hit/miss. If you take a look at http://www.theregister.co.uk/2012/07/12/velobit_demartek/ for example, some of these products don't seem to do anything - while some seem to actually work.

Like any young industry, it'll probably a while to shake out field until only a few decent contenders remain.

Re:I have seen SSDs used just to load the OS

[jedidiah]

> And you think a drive with actual moving parts will live forever?

Compared to how long SSDs have been in wide use, there are plenty of hard drives with "actual moving parts" that have lived forever.

However, the key thing is that you get some warning with a hard drive rather than it being sudden death.

Some SSD brands make Seagate seem reliable in comparison.

Surprisingly why?

[Sycraft-fu]

It would be surprising if it weren't the case. We've been doing the same thing with memory for years. Our CPUs need memory that can perform in the realm of 100GB/sec or more with extremely low latency, but we can't deliver that with DRAM. So we cache. When you have multiple levels of proper caching you can get like 95%+ of the theoretical performance you'd get having all the RAM be the faster cache, but at a fraction of the price.

This is just that taken to HDDs. Doesn't scale quite as well but similar idea. Have some high speed SSD for cache and slower HDD for storage and you can get some pretty good performance.

I love Seagate's little H-HDDs for laptops. I have an SSD in my laptop, but only 256GB. Fine for apps, but I can't hold all my data on there (music, virtual instruments, etc). They are just too pricey to get all the storage I'd need. So I also have an H-HDD (laptop has two drive bays). It's performance is very good, quite above what you'd expect for a laptop drive, but was only $150 for 750GB instead of $900 for 600GB (the closest I can find in SSDs).

Re:Surprisingly why?

[dbIII]

I think that RAM is dirt cheap, and storing local copies in RAM

A decent OS (back down MS fanboys, Win7 fits sometimes too) uses RAM to cache a lot of stuff anyway without the hassle of a ramdisk. That file you opened yesterday may still be in RAM and open very quickly if you have enough spare memory.
Sometimes they work well though. It's nice to have a 20GB ramdisk for scratch space for software that is too braindead to use memory when it's available and just hammers the disk instead. I've got two orders of magnitude in speed improvement on some closed source commercial software on linux just by feeding it a ramdisk.

Re:I have seen SSDs used just to load the OS

[John Bokma]

http://maxschireson.com/2011/04/21/debunking-ssd-lifespan-and-random-write-performance-concerns/ No idea how correct this is, but I bookmarked this over a year ago.

Pointless

[AlienIntelligence]

SSD's were recently @ $1/Gig. That's when I upgraded everything.

I've seen them as low as 55-65c a gig now. Yeah... gotta love how
tech drops in price RIGHT AFTER you decide to adopt.

Buy a WHOLE SSD drive. Put all the programs you use daily on it.

120G ~ $70

That is all.

FWIW, except for bulk storage, I will NEVER buy a spinning HD again.
I experienced a RIDICULOUS speed up, going from a 7200rpm drive.

-AI

Re:Pointless

[Mashiki]

To be honest, despite the dire doom and gloom warnings of people that the "end times will come" to first generation adopters of SSD's, I've got a first generation OCZ drive that's still chugging along and working like the day it was new. Heck, my page file is on it. It hasn't even used any of the backup blocks yet, 3 years on now and no complaints yet. I have a second 60GB drive that I transfer stuff on to if I'm using it alot, like MMO's and some programs that use large textures(Shogun2, Skyrim and so on) just to cut down on the load times.

Everything else? Yeah, it's dumped onto my 1TB and 2TB drives.

Not confined to high-end.

[jibjibjib]

> In reality, the shift from hard drives (HDDs) to SSDs has thus far been confined to the upper end of the PC market.

Not entirely. I have the cheapest netbook I could find, and I replaced its hard drive with a cheap low-capacity SSD. I don't keep much big stuff on it so the capacity isn't a problem. In terms of performance and power usage and not having to worry about my data when I drop my computer, it's been entirely worth it.

Re:I have seen SSDs used just to load the OS

[stewbacca]

...there are plenty of hard drives with "actual moving parts" that have lived forever.

Hmmm, been using 'puters since 1984 and still haven't found one that has a hard drive that, a) lived forever, or b) gave me a warning before it died a horrible death.

Seriously awful technology that is long overdue for an overhaul.

Re:bad review, what about hybrid drives?

[Lumpy]

Under a simple OS like windows? yes, I added one to my work PC and it flies. I then got another for my mac book pro and it flips out causing problems. same goes for using it under linux. It seems that more advanced filesystems and OS's that do a lot of housekeeping to the drive will freak these drives out.

Luckily I was able to sell my second drive to a friend who could use it in his windows laptop.

Only new for the consumer...

[phoebus1553]

This is exactly what has been going on in the enterprise storage space for a while. I only know much about two vendors, but they both have a solution like this. High end IBM storage has EasyTier, which while originally for the mix of FCAL/SAS to SATA, it works with SSD too, and in the latest revs all 3 tiers at the same time. NetApp used to have a PAM card which is now called... FlashCache? FlexCache? F-Something-Cache anyway, which is essentially an SSD drive on a PCI card.

Good to see the high end tech being applied to consumer level workloads.

No mention of OS requirements

[antifoidulus]

The article doesnt mention any other software(mostly OS) requirements for the accelerators, which is a pretty big deal. Basically there are 2 ways to cache:
1. On the file level, which isnt very resource intensive(there aren't nearly as many files as blocks on a disk), but requires that the accelerator be able to read file system metadata(and of course be able to intercept OS calls) which severely restricts what kind of file system, and really even operating systems, you can use with the accelerator
or
2. Block-level caching. Much more generic, can really be used with any file system as the blocks, not any file system metadata, are the only thing that is used. However managing all that block information comes at a cost, either in main memory or more expensive hardware. For instance Flashcache requires about 500 megs of memory to manage a 300GB disk. Depending on your usage this may be acceptable(though is memory really that much cheaper than ssds nowadays?) but for most it isnt.

From the article I can assume that they only tested Windows, and that really limits its usefulness.

In reality?

[kwerle]

In reality, the shift from hard drives (HDDs) to SSDs has thus far been confined to the upper end of the PC market.

In reality, 100% of the smartphones, tablets, many/all? of the ultrabooks, and many notebooks now ship with SSDs. In a short time, virtually all laptops will ship with SSDs.
Disks will go the way of tapes. You'll be able to get them, but the practical uses will be few.

In reality, I imagine that more computers (yeah, I count smart phones and tablets) are now sold with SSDs than disks.

As to your actual question about accelerators - I have no idea. I went solid state a couple of years ago and won't be going back.

Simpler solutions tend to be superior.

[Above]

SSD prices have fallen quickly, while hard drives have gone up. If you don't need large amounts of storage it's better to just go SSD. But what if large amounts of storage are needed?

I would recommend buying an SSD, putting the OS and all applications on it, and then using a magnetic drive as the "users" volume. Any sanely laid out OS makes this very easy. The OS and Apps will load quickly, the large items (like video) will be stored on the cheaper, larger disk storage. No "hybrid" algorithm to worry about working. Two separate parts that can be upgraded independently. No OS support required. Perhaps some acceleration of some small data files will be missed, but the large ones would have never fit in the accelerated flash anyway.

I do think that file systems need to evolve in a new direction. ZFS is a preview in the right direction, but it would be nice to have a file system where you could add ram disk, or flash disk and tell it to be used as a "cache" for underlying disk, write through or write back. Easy to do in software. Plus better backup and replication support. I'd really like to configure my laptop with a 2TB spining disk, 256G super-fast SSD, and give 1G of RAM to the file system. Tell the file system to write everything through to magnetic, cache frequently used in SSD and RAM. When I'm on the hope network replicate the spinning disk to my NAS bit for bit. Perform incremental backups to my cloud backup service when connected to a fast enough network using compressed incremental to save space. Give me all that with ZFS's other features and it would be sysadmin filesystem nirvana...

Re:Simpler solutions tend to be superior.

[gman003]

I would recommend buying an SSD, putting the OS and all applications on it, and then using a magnetic drive as the "users" volume. Any sanely laid out OS makes this very easy.

Just an FYI for everyone, Windows does not count as a sane OS for this purpose. I managed to render a Windows install unusable trying to do that.

The best trick is to move just specific user's folders, not the whole Users directory, over, and then symlink it back to the original location. Trying to move the entire \Users folder almost always breaks something, often rendering it impossible to log in. Other methods either require setting up your own unattended install disks with odd config files, or do not work completely.

The general process:
1) Install Windows to the SSD as normal
2) Create a user account and a backup account. For this demonstration, their original, default home folders will be C:\Users\GMan and C:\Users\Admin
3) Reboot (to log both out completely)
4) Log into the backup account, otherwise the system will choke while copying your registry files
5) use Robocopy to copy the user folder to the hard drive (robocopy C:\Users\GMan D:\Users\GMan /COPYALL /E)
6) Delete the user folder (rmdir C:\Users\GMan)
7) Symlink the folder on the hard drive back to the SSD (mklink /J C:\Users\GMan D:\Users\GMan)
8) Repeat for any other users, but note that you only need one "backup" account

This gives a few advantages:
1) It works transparently with programs that assume you are at C:\Users\[username]
2) It copies all user data, not just documents/images/videos
3) If the hard drive fails, you don't break the OS - you can log in using the alternate account (Admin in my example) to try to recover things
4) If you really wanted to, you could try to set some specific files in your user directory to be on the SSD
5) If you have a Windows install, or at least recovery partition, on the hard drive, either drive can fail without rendering the system unusable.

Re:Simpler solutions tend to be superior.

[Above]

Uh, Windows is sane for this purpose, and this is commonly done in corporate environments, keeping all user data on an CIFS share.

http://www.pcworld.com/article/190286/move_your_data_to_a_safer_separate_partition_in_windows_7.html

Basically install windows to C:, the SSD.

Spin up D:, the magnetic storage.

Create D:\Users\

Change the users home directory (My Documents) in the user properties to D:\Users\ (corp environments would be something like \\userserver\Users\).

It's more or less the same thing as changing your home directory path on a Unix machine.

Windows does not like Symlinks.

what an ugly bandaid

[parshimers]

i dont know about windows, but, wouldn't a more elegant way to accomplish this be paging? having a very large swap on the SSD portion and a very high swappiness value would sort of do what this intends to do, without such an end-run around the entire cache architecture of the OS

Re:I have seen SSDs used just to load the OS

[Bengie]

1MB/s will only take 30 years!

256GB
assume 20% over-provisioning
307.2GB * 3000 writes = 921,600GB
921,600 * 1024 = 943,718,400MB
943,718,400 / 3600(hours) / 24(days) / 365 (years) = 29.925years

With all programs opened, HD IO is closer to low 10s of KB/sec, not MB. Most of my IO is network traffic.

After a year of randomly benchmarking my SSD, having to reinstall Windows and 100GB of games a few times due to mistakes, it still is at 0% worn. At this relatively heavy usage rate, it will take more than 100 years to burn it out.

Single Article - Multiple Pages

[Taco Cowboy]

TFA at extremetech isn't that feature rich, nor embarking on a brand new frontier that none of us had ever been

TFA could have been made into ONE PAGE, but no, extremetech ain't gonna let us, the readers, enjoy it in one shot - we had to click through all the 5 pages

Please, Slashdot !

Next time you give us a link to a single TFA with multiple pages, please indicate it right upfront

Thank you !
 

Re:Single Article - Multiple Pages

[sortius_nod]

Not only this, the claims are at least 12 months out of date. SSD's are now less than $1/GB, & the average drive sold now is 120 or 128GB.

I upgraded my desktop with a cheap solution (AMD A8, 990FX, 16GB RAM, 128GB SSD, 2TB HDD) all for less than my last upgrade cost ($669 vs $955) 3 years ago. SSDs are definitely part of the norm now, we order many machines with dual 128MB SSDs in them, both laptops & desktops. The price difference is negligible, so this article seems more like a cry by someone attempting to hold onto the old way of doing things.

Re:Single Article - Multiple Pages

[obarthelemy]

Not all of us are gamerz ?

Re:Single Article - Multiple Pages

[jawtheshark]

AMD A8 (and A6 and A4) have a graphics core on board. Those graphics cores even are quite sufficient for non-hardcore gaming. I'm a fan of the FM1 platorm, and think it is way underrated. It has decent processing power, decent graphics, is very quiet (even with stock cooler) and not expensive at all. Example: A6-3650 (86.90€), 2x8GB kit RAM DDR3-1333 from ADATA (67.98€), motherboard GIGABYTE GA-A75-D3H (99.90€). That's quite some power for 254.78€ (including taxes, excluding shipping -- prices taken at Alternate). Like many of us, we just reuse the disk and the case we already own. There is no need for a graphics card in such a system, unless you're a hardcore gamer.

ZFS caching

[liquidhokie]

ZFS already supports flash devices for caches. For read caching (L2 ARC), you can create striped cache volumes. You get better speed that way, and if one of the devices fails, ZFS knows it and just goes straight to the main storage volume (the one being cached). Meanwhile, the other drive continues. For write caching (ZIL), since the data is "worth" more, you can create a mirror of flash devices. The benefit of the ZIL is realized even if the cache is small, but unfortunately SSD write speed can be worse than writing to regular drives (see below about SLC drives).

The best theoretical configuration would be, at a minimum:
- two small (and fast) SLC devices, mirrored and used for write caching
- two large(r) MLC devices, striped and used for read caching
- a redundant array of inexpensive drives (someone should come up with a catchy term for that), of huge capacity but otherwise slow (5400 rpm)

In place of the SLC drives, there are even more expensive (but higher performing) options, such as a bank of volatile RAM with a battery backup, and an SSD that the RAM contents get copied to in case of a power loss. These exist, and really work. The theory of a pyramid of caching; with "slower and cheaper" at the base and "faster and pricier" towards the top really has been shown to work.

ZFS can do all of this right now, and continuing a little off topic... can also do compressed incremental volume snapshots sent into the cloud :)

Yeah, I do a lot of work with ZFS. All of this stuff really works.

Re:SSD Reliability

[Anonymous Coward]

Dude, that is the 5,000 hour bug.

Update the firmware.

http://bit.ly/O1Fvzj

http://hothardware.com/News/Crucial-Acknowledges-Weird-5000-Hour-M4-SSD-Bug-Promises-Firmware-Fix-in-MidJanuary/

http://www.crucial.com/support/firmware.aspx

complete BS

[slashmydots]

SSD aren't just for high end systems. Out of my 300 or so past customers, approx 3 filled their hard drives to over 60GB total. I built several Kingston HyperX 90Gb and OCZ Agility 4 128GB drives without problems and they were all $500-600 final cost. I use an H77MA-G43 from MSI + 4GB Gskill 1333-CL7 memory and i3-2100 or 4GB 1333-CL9 and a Pentium B940-960. Put it in a decent $30-40 case, use an Antec VP450 or Basiq or other respectable but medium end PSU, and wait for a sale on Win7 64-bit OEM copies for $80 instead of $100 and you've got yourself an unbeatable, 7 year anticipated lifetime machine. Here's the kicker.

I have an i5 (sandy) ridiculous gaming computer with a GTS450, 8GB of CL7 RAM, P67 chipset, and a pretty fast 7200 RPM 1TB Seagate main drive. It's custom built and would be around $1000 retail at my shop (at the time at least). It takes over a minute to log in and it takes forever to load games.

I also built a system I'm selling for $520 with a Pentium B950, 4GB of pretty standard RAM, and a Maplecrest 60GB SSD. It logs into Windows in 4 seconds. The glowing balls don't even touch while loading the Windows 7 logo.

SSDs are not for high end systems only! They're specifically exactly the opposite. They're the best way to make a really cheap budget PC seem extremely fast.

Re:I have seen SSDs used just to load the OS

[0123456]

last year is years ago?

Indeed. The drive didn't even exist 'years ago'.

Someone below posted a similar bug with a different model of SSD. 'Update the firmware' seems to be a regular occurrence once you start using SSDs; so far I've never had to update the firmware on a hard drive.

Worst of both worlds

[WaffleMonster]

Hybrid drives have been on the market for years. It seems to me your risk exposure is only increased by combining the two. You now have to worry about the perils of spinning platters, oxide eating flash write operations and new management technology gluing the systems together not widely deployed.

The last I checked about a year ago there were overwhelming negative comments related to reliability of hybrid drives. Even assuming all the bugs have since been worked out seems like such a fleeting and pointless stop-gap measure as to not be worthwhile.

I have enough memory that most applications load instantly from the operating system cache. 32GB of ddr is readily available for less than $200 ... nothing involving a SATA bus can be faster than the operating systems main memory disk cache.

Hopefully memristers or other technologies will pan out soon and we can be done with slow, power hungry access and inherently unreliable storage mediums once and for all.

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[account_deleted]

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Have tested Intel's solution a bit..

[Terrasque]

When I got my new Z77 board last week, I managed to slice my 120gb SSD into two parts. 18gb for Intel's cache system, and rest for "Data" - aka Windows install.

I configured the SSD to cache my 2tb spinney a bit, and it generally worked as expected. Performance ranged from clean SSD speed some places, to in worst case old HDD speed.

In other words, worst-case scenario was same as not having cache, and best-case scenario made it look like a 2TB SSD at no extra cost :)

I've currently disabled it, since currently I'm re-installing my steam games (over 300 in total..), but will re-enable it when the data is a bit more static again.

So far I consider the experiment a huge success, even though it complicated the install somewhat (SSD cache can only be configured from Windows, and only if the SSD is not running the OS).

SSD makers got greedy

[gelfling]

The cost benefit of SSD's barely makes sense - the makers got greedy and decided to tack absurd price premiums on their gear far in excess of their benefit. And they've stayed there.

No Good if Not Transparent

[EmagGeek]

If it requires O/S level drivers to implement the cache, then it's NFG.

SSD caching has promise, but it needs to be done in hardware, and be completely transparent to the O/S on top of it.

Say what?

[DeadCatX2]

Absolute minimum latency for a fetch is 16ms on USB port

Where are you getting this number? I develop USB devices (Cypress FX2 Hi-Speed and a PIC for Full-Speed), and a USB Hi-Speed microframe is transmitted every 125 microseconds. When I initiate transfers, they almost always go out during the next microframe. I can and have sent two packets back and forth in a single millisecond, and that's without sending multiple packets per microframe (I believe I've seen up to 17 bulk packet transfers in one microframe before in a Cypress app note comparing bulk to isochronous).

The only USB devices I'm aware of with such poor latency are keyboards and mice, because they're generally low-speed devices.

Is this 16ms fetch latency some artifact of the OS? Because it's certainly not a limitation of the hardware and software, as I can personally attest to.