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When Solid State Drives Are Not That Solid

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Re: When Solid State Drives Are Not That Solid

#61

Post by [deleted] »

derefr wrote: post #40
madez wrote: post #38

Earlier quoted context omitted.

There is no cloud - just other people's computers. Many use-cases just require the job to be done on your computers due to security and privacy reasons. Yes, Amazon's and Google's services are in some ways less secure than your own computer, because they are hosted by companies which are subject to a government that doesn't value privacy, not even of it's own citizens. That means said government can, just to give a c…

Thinking about individual computers will lead you astray. There are, rather, sets of machines (from single boxes to entire data-centers) that are managed by a given sysadmin staff. The more machines they manage, the more likely it is that problems will have institutionalized and operationalized solutions. A cloud is just a sysadmin staff with a Sufficiently Large Deployment to have ironed out all the kinks in their h…

[deleted]

Re: When Solid State Drives Are Not That Solid

#62

Post by bad_user »

ploxiln wrote: post #14
bbcbasic wrote: post #11

I have a Samsung SSD 850 PRO 512GB in my Windows PC. And I have TRIM enabled in Windows: > fsutil.exe behaviour query DisableDeleteNotify DisableDeleteNotify = 0 Should I be worried?

Released versions of Windows do not use queued trim. (That's why serious bugs like this can happen ;)

The problem exposed in the article is about un-queued trim.

Re: When Solid State Drives Are Not That Solid

#63

Post by baruch »

cft wrote: post #28

Using SAS SSD drives on a server is a bad idea for many reasons. One should use PCIe cards, that sit directly on the PCIe bus, such as FusionIO or SanDisk. They have been tested and retested (e.g. by Facebook), without the unnecessarily added complexity of SAS/SATA protocols. The I/O performance is also about 20x.

I don't think that testing by Facebook is going to help you unless you are using the exact same model as they are and are assured of using their exact firmware. At work we use SAS SSDs in large quantities and the firmware we use is customized to us (based on the mainline one). Do not assume that a bug that was fixed in our firmware was necessarily fixed in the normal one. One would think it would but it is possible that it wasn't ported to the mainline firmware.

Re: When Solid State Drives Are Not That Solid

#64

Post by KaiserPro »

jlebar wrote: post #36

To me, this sort of thing brings home the value of not running your own machines. Sure, Amazon's/Google's clouds have quirks, but it's far less likely that you're going to have to debug faulty hardware in this way. It sounds like a team of more than one person worked on this at least part-time for weeks -- how much is that worth? It's not just the cost of hiring extra people to do the work; often small companies simp…

Lets do some maths on that claim: AWS: c3.8xlarge with 32 "CPUS" and 60 gigs of ram.

For the machine alone its $1200 a month. Bear in mind its on a shared infrastructure, with noisy neighbours. You'll see about 10-30% CPU steal. In practice you'll see performance about half that of a real machine (from my comparisons)

Then you'll need to factor in disks as well. First things first EBS is dogshit slow. Yes ephemeral disks are fast, but then they die, so you're in the same situation. however you need 10gig networking to get low latency, avoid puncturing the cache etc,etc,etc,

for EBS the maximum IOPs you can guarantee to get is 20,000, and you need 1tb for that.

for the Iops, thats $1300 a month + $125 for the 1 TB of storage.

so a month, per machine it'll be $2625. $31500 per machine, per year.

Every 6 months, you could buy a new machine, which is faster than the fastest EC2 instance + EBS.

Now, the OP stated that they have more than one machine. Obviously one could use reserved instances. However similarly one could negotiate volume discounts.

There is of course the cost of internet and cooling, you're looking at around $500 a month for half a rack, depending on power consumption. (if you're colo'ing)

From a valuation point of view, having hardware counts towards your value, as its an asset you actually own. More importantly you can use it to lower your tax bill, and reduce your run rate, in exchange for an up front cost.

Now, if you have a lot of bursty traffic, that doesn't require much DB activity, then AWS is perfect, as the elastic IP load balancer allows you to spin up machine on demand. However thats not that helpful for Databases. Sure you can warm migrate from a EBS snapshot, but you'd best do it quick, otherwise you'll overload an already overloaded DB.

Re: When Solid State Drives Are Not That Solid

#65

Post by icebraining »

hvidgaard wrote: post #58
jhead wrote: post #51

Earlier quoted context omitted.

Agreed. Additionally, some business models simply don't mesh with cloud infrastructure pricing no matter the volume. There are definitely advantages to using cloud services, but most of the time bare metal gets you more hardware/performance at a lower cost in the long run, even when you factor in everything else that it entails.

The thing people forgets, is that the cloud provider have the same issues and expences. That cost is passed on to the clients. Now they may be more efficient ect. but once you reach a certain scale, and it's less that people think, you might as well get it done in house if you can find qualified people.

How can people forget, when that cost is right there in the price tag? If anything, it's easier to overlook the costs of running your own hardware, since they aren't immediately apparent.

Re: When Solid State Drives Are Not That Solid

#66

Post by MrBuddyCasino »

Not directly related to TRIM, but AeroSpike has a nice test suite for SSDs, probing for IOPS and latency: https://github.com/aerospike/act

They share their test results for both physical and cloud-based storage, I figured this would be of interest:

http://www.aerospike.com/docs/operations/plan/ssd/ssd_certif...

Re: When Solid State Drives Are Not That Solid

#67

Post by pjc50 »

derefr wrote: post #40
madez wrote: post #38

Earlier quoted context omitted.

There is no cloud - just other people's computers. Many use-cases just require the job to be done on your computers due to security and privacy reasons. Yes, Amazon's and Google's services are in some ways less secure than your own computer, because they are hosted by companies which are subject to a government that doesn't value privacy, not even of it's own citizens. That means said government can, just to give a c…

Thinking about individual computers will lead you astray. There are, rather, sets of machines (from single boxes to entire data-centers) that are managed by a given sysadmin staff. The more machines they manage, the more likely it is that problems will have institutionalized and operationalized solutions. A cloud is just a sysadmin staff with a Sufficiently Large Deployment to have ironed out all the kinks in their h…

This is true but not relevant to the parent comment's concerns about security/privacy.

Re: When Solid State Drives Are Not That Solid

#68

Post by pjc50 »

caf wrote: post #31
madez wrote: post #25

It feels like Samsung used the Linux community here as a free testbed. Samsung knew that only Linux supported queued trim, so releasing it without proper testing is just externalizing the disproportionately increased cost of testing to the Linux community.

Is the loss of reputation really worth less than the value of the externalised testing?

Loss of reputation isn't a real thing in this industry. Pretty much all hard drive manufacturers have had high-profile "bad" models, for example.

Re: When Solid State Drives Are Not That Solid

#69

Post by eveningcoffee »

sengork wrote: post #39
bbcbasic wrote: post #11

I have a Samsung SSD 850 PRO 512GB in my Windows PC. And I have TRIM enabled in Windows: > fsutil.exe behaviour query DisableDeleteNotify DisableDeleteNotify = 0 Should I be worried?

Install the Samsung Magician Toolbox for best results on Windows platforms: www.samsung.com/samsungssd/

When you do this, read what they claim in ToS.

Re: When Solid State Drives Are Not That Solid

#70

Post by Aardwolf »

"Samsung SSD 850 PRO 512GB recently blacklisted as 850 Pro and later in 8-series blacklist"

That's what I have in my home computer, with ArchLinux.

Do you think this problem only is something particular in the servers of the author of that article, or should this be interpreted as:

linux + samsung 850 = you will lose your data?

Thanks...

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