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What we learned about SSDs in 2015

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Re: What we learned about SSDs in 2015

#91

Post by cnvogel »

ScottBurson wrote: post #70
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.

I still don't trust SSDs as much as I do spinning disks. While neither kind of drive should be trusted with the only copy of important data, I would say that drives used for backup, or for access to large amounts of data that can be recovered or recreated if lost and where the performance requirements do not demand an SSD, might as well be HDDs -- they're cheaper, and arguably still more reliable. If the workload is…

Anecdotal evidence: 2.5" SATA HDD failed for me suddenly just last Tuesday, SMART was fine before, both the attributes and a long (complete surface scan) selftest I did a few weeks ago after I got this lightly used notebook from a colleague (I only needed for tests).

I think what people experience is that the sudden death of SSDs doesn't occur more often than on HDDs. But with the mechanical issues and slowly building up of bad sectors gone, sudden death is probably the only visible issue left.

(Just my personal opinion.)

Re: What we learned about SSDs in 2015

#92

Post by otakucode »

Can't wait for the inevitable discovery that NAND chips are being price-fixed. You would think after the exact same companies price-fixed RAM and LCD panels that peoples radars would go off faster. You expect me to believe that the metals and neodymium magnets and now helium containing drives are cheaper to manufacture than an array of identical NAND chips? NAND chips which are present in a significant percentage of all electronic products purchased by anyone anywhere? When a component is that widely used, it becomes commoditized. Which means its price to manufacture drops exponentially, not linearly like the price drops of NAND has done. This happened with RAM and LCDs as well. When you can look around and see a technology being utilized in dozens of products within your eyesight no matter where you are, and those products are still more expensive than the traditional technology they replace, price-fixing is afoot.

I am open to being wrong on this, but I don't think I am. Can anyone give a plausible explanation why 4TB of NAND storage should cost more to manufacture than a 4TB mechanical hard drive does, given the materials, widespread demand for the component, etc?

Re: What we learned about SSDs in 2015

#93

Post by [deleted] »

vbezhenar wrote: post #9

May be SSD should add something like "raw mode", when controller just reports everything he knows about disk, and operating system takes in control the disk, so firmware won't cause unexpected pauses. After all, operating system knows more, what files are not likely to be touched, what files are changing often, etc.

[deleted]

Re: What we learned about SSDs in 2015

#94

Post by otakucode »

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.

Sure. My first purchase of SSDs were 3 80GB Intel SSDs which I put into RAID-0 and used for my primary system drive on my gaming machine. RAID-0 provides very-near 100% performance boost per drive added. Of course, it also provides the same bonuses to the likelihood of total data loss... but that was a risk I was OK with taking (and which never bit me!).

Re: What we learned about SSDs in 2015

#95

Post by im2w1l »

bigiain wrote: post #78
ersii wrote: post #66

Earlier quoted context omitted.

What kind of video servers are you talking about? For ingesting from a feed/camera in? Streaming out video? Curious.

A friend of mine does a lot of programming and installations using Dataton Watchout - where they use 4 or more 4K projectors stitched together into one big image. He's regularly got war stories about problems with the latest batch of SSDs not playing well in RAID0 causing stutters on simultaneous playback of multiple 4K video streams.

Is there an advantage compared to putting each stream on a different drive?

Re: What we learned about SSDs in 2015

#96

Post by leonroy »

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…

We ship voice recording and conferencing appliances based on Supermicro hardware, a RAID controller and 4x disks on RAID 10.

We tried to mitigate the failure interval on the drives by mixing brands. Our Supermicro distributor tried to really dissuade us from using mixed batches and brands of SAS drives in our servers. Really had to dig in our heels to get them to listen.

Even when you buy a NAS fully loaded like a Synology it comes with the same brand, model and batch of drives. In one case we saw 6 drive failures in two months for the same Synology NAS.

Wonder whether NetApp or EMC try mixing brands or at least batches on the appliances they ship?

Re: What we learned about SSDs in 2015

#97

Post by pjc50 »

otakucode wrote: post #92

Can't wait for the inevitable discovery that NAND chips are being price-fixed. You would think after the exact same companies price-fixed RAM and LCD panels that peoples radars would go off faster. You expect me to believe that the metals and neodymium magnets and now helium containing drives are cheaper to manufacture than an array of identical NAND chips? NAND chips which are present in a significant percentage of…

"Apples do not cost the same as oranges, therefore oranges are being price-fixed" is not a convincing line of reasoning. The two technologies are very different and NAND storage is much newer, and has always been much more expensive than disk storage.

The correct thing to compare NAND prices to is other chips that are being fabbed at the same process node, by die area.

Re: What we learned about SSDs in 2015

#98

Post by fulafel »

tw04 wrote: post #25
velox_io wrote: post #22

The most exciting recent development in SSDs (until 3DXpoint is released), is bypassing the SATA interface, connecting drives straight into the PCIe bus (no more expensive raid controllers). Just a shame hardly any server motherboards come with M.2 slots right now. The 4x speed increase and lower CPU overhead means it is now possible to move RAM only applications (for instance in-memory databases) to SSDs, keeping on…

How exactly does connecting to the PCIe bus obviate the need for RAID? RAID isn't about connecting drives, it's about not losing data. If you don't need RAID for your application today, you can purchase a non-RAID SAS adapter for a couple hundred bucks, or just use the onboard ports that are sure to be there.

> RAID [...] it's about not losing data

It's a pretty ineffective way to guard against data loss, you need backups.

RAID [1-6] is an availability solution, saving the downtime of restoring from backup in the case of the most predictable disk failures. It doesn't help with all the other cases of data loss.

Re: What we learned about SSDs in 2015

#100

Post by pjc50 »

burntwater wrote: post #86
ersii wrote: post #66

Earlier quoted context omitted.

What kind of video servers are you talking about? For ingesting from a feed/camera in? Streaming out video? Curious.

While these servers can ingest video feeds, they wouldn't (typically) be saving the incoming feeds. These servers play out video over many projectors blended into a single seamless image. If you've watched the past few Olympics opening ceremonies, you most certainly saw the projections. My recent project, which was relatively small, played back a single video over 4 blended projectors. Each video frame was a 50MB unc…

Each video frame was a 50MB uncompressed TGA file, 30 times a second.

Ouch! Not even a PNG?

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