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What we learned about SSDs in 2015

zdnet.com

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Re: What we learned about SSDs in 2015

#51

Post by MichaelGG »

toomuchtodo wrote: post #48
lsc wrote: post #35

Earlier quoted context omitted.

uh, this shouldn't be voted down. Now, I don't use RAID for performance, I use raid for reliability, like parent said, and I've never actually been in a position where it would make sense, but people do use raid0 to increase performance. It happens, even if it's not nearly as common as using raid to prevent data loss.

Back in the day, folks would RAID0 AWS EBS volumes to get the level of performance they needed (this was long before SSD EBS volumes).

This is still (AFAIK) the recommended way to get higher IOPS out of Azure SSDs.

Re: What we learned about SSDs in 2015

#52

Post by pkaye »

ddorian43 wrote: post #16
acquacow wrote: post #12

...unless you are Fusion-io, in which case, most of these problems don't affect you.

why? isn't fusion-io based on ssd ?

They have a special OS driver which moves the FTL closer to the OS. So one of the things they need is multi GB of memory from the OS to keep the FTL mapping tables. Also sudden power loss requires OS intervention to piece back the FTL structure (I seem to recall the original product taking 5 minutes to recover.) This also means you couldn't boot from an Fusion IO drive. I'm not sure if they fixed these issues on a more recent drive.

Re: What we learned about SSDs in 2015

#53

Post by arielweisberg »

TeMPOraL wrote: post #41
ComputerGuru wrote: post #8

Kind of stupid to end with "Since CPUs aren't getting faster, making storage faster is a big help." CPUs and storage exist for completely disjoint purposes, and the fastest CPU in the world can't make up for a slow disk (or vice versa). Anyway, CPUs are still "faster" than SSDs, whatever that means, if you wish to somehow compare apples to oranges. That's why even with NVMe if you are dealing with compressible data e…

Ever tried to play a modern computer game? You never have enough RAM for stuff; a lot of content gets dumped onto hard drive sooner or later (virtual memory), or is be streamed from the drive in the first place. Having faster access helps tremendously. From my observation, actually most personal and business use machines are IO-bound - it often takes just the web browser itself - with webdevs pumping out sites filled…

For years total available RAM could easily exceed the install size of entire and entire game thanks to consoles holding everything back.

And by exceeded I mean the games were 32-bit binaries so the ram left over was enough to cache the entire game data set even in light of RAM used by the game.

Recently install size seems to have grown quite a bit.

Re: What we learned about SSDs in 2015

#54

Post by burntwater »

lsc wrote: post #35
tehwalrus wrote: post #29

Earlier quoted context omitted.

> RAID isn't about connecting drives, it's about not losing data. RAID-0 is used as a way to get faster performance from spinning disk drives, as you can return parts of each read request from different (striped) drives. You also get better write performance, as your writes are split across the drives.

uh, this shouldn't be voted down. Now, I don't use RAID for performance, I use raid for reliability, like parent said, and I've never actually been in a position where it would make sense, but people do use raid0 to increase performance. It happens, even if it's not nearly as common as using raid to prevent data loss.

High-end video servers used in the entertainment industry typically use RAID 0. My last project, for example, used 10 250GB SSDs in RAID 0.

Re: What we learned about SSDs in 2015

#55

Post by Laforet »

nostrademons wrote: post #49
ak217 wrote: post #40

This article has a lot of good information, but its weirdly sensationalistic tone detracts from it. I appreciate learning more about 3D Xpoint and Nantero, but SSDs are not a "transitional technology" in any real sense of the word, and they won't be displaced by anything in 2016, if nothing else because it takes multiple years from volume capability to stand up a product pipeline on a new memory technology, and more…

I got the sense that it was a PR hit for Nantero, bought and paid for. Notice the arc of the article: it says "[Popular hot technology] is dead. [Big vendors] have recently introduced [exciting new product], but [here are problems and doubts about those]. There's also [small startup you've never heard of] which has [alternative product] featuring [this list of features straight from their landing page]." Usually thes…

Robin Harris has been advocating for the abolishment of block abstraction layer for a couple of years now and this piece is consistent with his usual rhetoric

Re: What we learned about SSDs in 2015

#56

Post by wtallis »

lsc wrote: post #43
wtallis wrote: post #42

Earlier quoted context omitted.

You need to be more precise with your terminology. There is no such thing as a NVMe backplane. NVMe is a software protocol. The backplanes for 2.5" SSDs to which you refer would be PCIe backplanes using the SFF-8639 aka U.2 connector. None of the above is synonymous with the M.2 connector/form factor standard, which is what I was talking about.

edit: okay, I re-read what you said and yes, these won't support M.2 drives, if I understand what's going on here, and it's possible I still don't. (I have yet to buy any non-sata SSD, though I will soon be making experimental purchases.) I was talking about these: http://www.supermicro.com/products/nfo/NVMe.cfm Note, though, it looks like if you are willing to pay for a U.2 connected drive, you can get 'em with the…

Take a look at how much stricter the temperature and airflow requirements are for Intel's 2.5" U.2 drives compared to their add-in card counterparts. (And note that the U.2 drives are twice as thick as most SATA drives.)

M.2 has almost no place in the server market. U.2 does and will for the foreseeable future, but I'm not sure that it can serve the high-performance segment for long. It's not clear whether it will reach the limits on capacity, heat, or link speed first, but all of those limits are clearly much closer than for add-in cards.

Re: What we learned about SSDs in 2015

#57

Post by Dylan16807 »

nostrademons wrote: post #49
ak217 wrote: post #40

This article has a lot of good information, but its weirdly sensationalistic tone detracts from it. I appreciate learning more about 3D Xpoint and Nantero, but SSDs are not a "transitional technology" in any real sense of the word, and they won't be displaced by anything in 2016, if nothing else because it takes multiple years from volume capability to stand up a product pipeline on a new memory technology, and more…

I got the sense that it was a PR hit for Nantero, bought and paid for. Notice the arc of the article: it says "[Popular hot technology] is dead. [Big vendors] have recently introduced [exciting new product], but [here are problems and doubts about those]. There's also [small startup you've never heard of] which has [alternative product] featuring [this list of features straight from their landing page]." Usually thes…

Eh, it listed it as "promises" and talked the same way about Adesto. It's reasonable to say "this is the basic claim of the product; we'll see if they get there" without it being PR.

Re: What we learned about SSDs in 2015

#58

Post by Thorbears »

bravura wrote: post #39

I need an external disk for my laptop that I leave plugged in all the time. What is the most reliable external hard drive type? I thought SSDs were more reliable than spinning disks, especially to leave plugged in constantly, but now I'm not as sure.

This article, and the majority of the comments here, are about using SSDs in server environments, where permanently high load and zero downtime is the norm. And it doesn't even seem to be about SSDs vs HDDs, it is about SSDs vs future technologies.

For personal use, SSDs outperform HDDs in just about every aspect, if you can afford the cost, an SSD is the better choice. And there is nothing mentioned here about downsides of leaving a drive plugged in and powered on at all times.

Re: What we learned about SSDs in 2015

#59

Post by watersb »

rsync wrote: post #15
_ak wrote: post #6

At one of my previous employers, they built a massive "cloud" storage system. The underlying file system was ZFS, which was configured to put its write logs onto an SSD. With the write load on the system, the servers burnt through an SSD in about a year, i.e. most SSDs started failing after about a year. The hardware vendors knew how far you could push SSDs, and thus refused to give any warranty. All the major SSD ve…

Just a note ... we use SSDs as write cache in ZFS at rsync.net and although you should be able to withstand a SLOG failure, we don't want to deal with it so we mirror them. My personal insight, and I think this should be a best practice, is that if you mirror something like an SLOG, you should source two entirely different SSD models - either the newest intel and the newest samsung, or perhaps previous generation int…

FWIW I bricked a very cheap consumer SSD by using it as write log for my ZFS array. This was my experiment machine, not a production server.

Fortunately I had followed accepted practice of mirroring the write cache. (I'd also used dedicated, separate host controllers for each of these write-cache SSDs, but for this cheap experiment that probably didn't help.)

So yes this really happens.

Re: What we learned about SSDs in 2015

#60

Post by jaysoncena »

jjtheblunt wrote: post #38
ddorian43 wrote: post #16

Earlier quoted context omitted.

why? isn't fusion-io based on ssd ?

fusion-io (i believe, but please verify online) uses a spinning drive for frequent writes and an ssd for frequent reads, with software deciding what goes where, lessening the write traffic to the ssd, and thus wear to it.

I think what you're trying to describe is apple's fusion drive.
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