
How DreamHost Builds Its Cloud: Selecting Hard Drives - kungfudoi
https://www.dreamhost.com/blog/2016/10/01/dreamhost-builds-cloud-selecting-hard-drives/
======
hackuser
There's something I don't understand about the enterprise vs consumer (or
"client") SSD classification: According to the widely quoted JEDEC standard,
JESD218A, [0] these are the date retention standards:

Retention Use (power off):

* Client: 30° C, 1 year

* Enterprise: 40° C, 3 months

It's not a typo, I've seen it in many places: It appears that the power-off
data retention standard is only 3 months in enterprise drives (1 year in
client drives isn't great either).

Can anyone explain it? My only guess is that the "enterprise" classification
refers to drives designed to churn data 24/7, not store it long-term. But I
think many people understand the term 'enterprise' to mean much greater
durability. I'd be very disappointed if I experienced dataloss from leaving
any drive on a shelf for 3 months, much less an expensive enterprise drive.
(Or maybe I misunderstand what's meant by _Retention Use (power off)_?)

[0] Available here: [https://www.jedec.org/standards-
documents/results/jesd218b.0...](https://www.jedec.org/standards-
documents/results/jesd218b.01) and quoted here in the table here:
[http://www.kingston.com/us/ssd/enterprise/best_practices/ent...](http://www.kingston.com/us/ssd/enterprise/best_practices/enterprise_versus_client_ssd)

~~~
ilaksh
How many studies have been done verifying that enterprise SSDs perform
significantly better than consumer SSDs in any metrics?

My belief is that the consumer SSDs actually have very similar performance and
reliability requirements to the enterprise because they are generally deployed
without redundancy, and so any failures can be catastrophic for consumers. And
then there are lots of consumers that will go on Amazon or Newegg etc. and
leave very bad reviews.

So I personally believe the 'enterprise' distinction is mostly a scam, and
developers who are looking for inexpensive hosting have been mainly waiting
for A) datacenter providers to realize that or B) a slow market perfusion that
mitigates it.

~~~
nmjohn
> How many studies have been done verifying that enterprise SSDs perform
> significantly better than consumer SSDs in any metrics?

Define perform. But short answer, lots.

To be fair, consumer SSDs these days are pretty solid, and will perform great
for most workloads - even many workloads which enterprise drives would be used
for.

The big difference though, is with extremely heavy write workloads. The
endurance of enterprise SSDs in terms of how much data you can write before
the drive will fail, is a couple orders of magnitude greater than consumer
drives. For example, I have an 800gb Intel S3710 SSD. It's rated to handle 10
DWPD (drive writes per day) - meaning that one could write 8,000 gigabytes of
data a day, 365 days a year, for 5 years (~17 petabytes), and the drive will
still be chugging away just fine.

A 1TB Samsung 850 Pro (which has some of best endurance of consumer ssds), on
the other hand is only rated to 300 terabytes of data written. So the
enterprise drive has a 60x improvement in endurance.

~~~
ilaksh
Do those ratings reflect actual tested durability or mainly marketing?

What is the real average durability requirement?

Have there not been some relatively large providers using consumer SSDs in the
datacenter successfully for some time?

~~~
nmjohn
> Do those ratings reflect actual tested durability or mainly marketing?

They reflect what the manufacturers will offer the warranty until. A quick
google search suggests about 2 petabytes of writes is the max you can get on a
samsung 850 before it completely fails (and after 1 petabyte you will have
many failed sectors and data corruption starts creeping in)

At the same time, I bought my S3710 used and when I got it, it had almost 8
petabytes written and it's still just like new.

> Have there not been some relatively large providers using consumer SSDs in
> the datacenter successfully for some time?

Yes, that wouldn't surprise me at all. Like I said, for many workloads,
consumer SSDs are acceptable. But that doesn't mean enterprise drives are a
scam.

------
justjonathan
This is only my personal experience, bu I am embarrassed to report that I have
been in DreamHost customer for over 10 years for hosting some small and
unimportant personal projects. I have been consistently disappointed with the
level of their engineering and systems. Their systems are unreliable, their
custom build ticketing system is atrocious. I would take any technical advice
from them with a handful of salt.

~~~
charliepark
As a counterpoint (and this is only my personal experience), but I'm happy to
report that I've been a DreamHost customer for over 10 years for hosting some
small and unimportant personal projects. I've been really happy with
everything. Not sure how our usage of their service differs (probably lots!),
but I would hate for people to dismiss DreamHost without hearing about a
positive experience with them.

~~~
alphapapa
Also been a customer for over 10 years. Mostly quite happy.

What bugs me about them most right now is their new control panel design. The
_log out_ link is at the _bottom left_ , so it gets _pushed off the screen_
when you expand the menus.

I have sent at least 3 tickets to them over the course of about 4 months
telling them that they need to move the log out link to the top of the page,
somewhere in the _copious_ amounts of empty space they have up there. They
have responded every time saying they would look into it, pass it along, etc.
But nothing's changed. I could fix it myself in 30 seconds by copying and
pasting the code in the template.

And I can't help but wonder, if they are so incompetent as to not realize
that, when the _log out link gets pushed off the page_ , their design is
_broken_ , what else are they incompetent with? Security? It doesn't take a
rocket scientist to see how broken it is--do their middle managers or higher-
ups not recognize the problem? If not, what other problems do they not
recognize? And if my messages to them are not getting through to those who
could fix them, that's a problem in their support system.

So I would keep an eye on them. I hope they are not beginning to decline.

------
hackuser
I recently looked at SSDs for a project I'm working on. By far, the biggest
performance impact is in using PCIe rather than SATA interfaces. (The
performance boost also may rely on M.2 and/or NVMe; because I don't have a
PCIe controller on the system I was working on, I didn't look into it
further). An example:

Samsung 850 Pro, reputedly one of the fastest SATA SSD drives (SATA 3, 2.5",
AHCI):

* Sequential read/write: 550/520 MB/s

* 4K random read: 100K IOPS

Samsung 950 Pro (PCIe 3.0 x4, M.2, NVMe):

* Sequential read/write: 2,500/1,500 MB/s

* 4K random read: 300K IOPS

Source: [http://www.anandtech.com/show/9702/samsung-950-pro-ssd-
revie...](http://www.anandtech.com/show/9702/samsung-950-pro-ssd-
review-256gb-512gb)

~~~
nickff
I use the 850 Pro, and it is very fast, but has many issues with Windows 7
(which is what I have).

~~~
whoopdedo
Care to elaborate? I was about to pick one up but now you have me hesitating.

~~~
rincebrain
I'm unaware of negative interactions with Win7 and the 850 Pro, having used
one in my Win7 desktop for over a year at this point.

I can't immediately find anything but one-off reports online that don't line
up with each other, either - maybe they're thinking of the 840 line?

~~~
nickff
Sorry, that was a typo, I have a 950 pro, and Windows 7 doesn't include an m.2
driver, which causes constant problems with booting and starting up after
crashes. The 850 and 840 are both great drives.

------
arca_vorago
I've been with drramhost for at least 10 years, but Im about to move
everything because of their recent move from open source webmails to only
atamail or whatever the new one is called. I spent a lot of time locking down
my squirrelmail install, only to login one day and be greeting by a completely
different client. Sure they had warnings, but none of those warnings clearly
stated the forced move, I thought I could opt out.

As for the rest of their service, Their actual server performance is decent,
but their VPS offerings dont seem competitive these days, so Im strugling to
find a reason to stay.

~~~
rileymat2
I had their VPS, but they do not give you root access. (In fact removed root
access from one I used for a few years, screwing a bunch of my stuff up). Kind
of a strange definition of VPS they have now.

~~~
dchest
This is managed VPS, which is kinda convenient if you don't want to manage
servers yourself. For the more "normal" unmanaged VPS with root access,
there's DreamCompute. It's even cheaper than DigitalOcean — $4.50 for 512 MB.
I recently switched [https://iwl.me](https://iwl.me) to it, and it works well.

~~~
rileymat2
That is fine, but I was using it before those restrictions, which is annoying.
Then I switched to Dream Compute and lost the email hosting for the domain.

~~~
dchest
Oh, I didn't know it was unrestricted before. (Re-read your comment) Yeah, not
good of them to remove such a major feature if it was there before.

Why did you lose email for domain? It seems like I still have this option for
the domain on DreamCloud (although I also still use their shared hosting).

------
killbrad
Forgive my ignorance, but how is this "cloud" instead of VPS?

