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SSDs have become fast, except in the cloud

databasearchitects.blogspot.com

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Re: SSDs have become fast, except in the cloud

#231

Post by [deleted] »

kwillets wrote: post #197
dan-robertson wrote: post #189

Earlier quoted context omitted.

Yeah, I’m curious how they would respond to the claims in the article. In [1], they talk about aiming for low latency, for consistent performance (apparently other SSDs could stall at inopportune times), and support on-disk encryption. Latency is often in direct conflict with throughput (eg batching usually trades one for the other), and also matters a lot for plenty of filesystem or database tasks (indeed the OP lin…

The Nitro chipset claims 100 GB/s encryption, so that doesn't seem to be the reason.

[deleted]

Re: SSDs have become fast, except in the cloud

#232

Post by adgjlsfhk1 »

dekhn wrote: post #205
mint2 wrote: post #166

Earlier quoted context omitted.

I don’t really agree with assuming the form of physical attachment and interaction unless it is spelled out. If that’s what’s meant it will be stated in some fine print, if it’s not stated anywhere then there is no guarantee what the term means, except I would guess they may want people to infer things that may not necessarily be true.

"Physically attached" has had a fairly well defined meaning and i don't normally expect a cloud provider to play word salad to convince me a network drive is locally attached (like I said, if true, I would need to have a chat with my TAM about it). Physically attached for servers, for the past 20+ years, has meant a direct electrical connection to a host bus (such as the PCI bus attached to the front-side bus). I'd l…

Ethernet cables are physical...

Re: SSDs have become fast, except in the cloud

#233

Post by sargun »

tptacek wrote: post #215
yolovoe wrote: post #195

Earlier quoted context omitted.

You’re wrong. Instance local means SSD is physically attached to the droplet and is inside the server chassis, connected via PCIe. Sourece: I work on nitro cards.

"Attached to the droplet"?

Droplets are what EC2 calls their hosts. Confusing? I know.

Re: SSDs have become fast, except in the cloud

#234

Post by [deleted] »

jiggawatts wrote: post #219
computerdork wrote: post #202

Earlier quoted context omitted.

Interesting. And would you happen to have the numbers on the performance of the local SSD? Is it's read and write throughput up to the level of modern SSD's?

It's pretty much like how the article said. The cloud local SSDs are notably slower than what you'd get in an ordinary laptop, let alone a high-end server. I'm not an insider and don't have any exclusive knowledge, but from reading a lot about the topic my impression is that the issue in both clouds is the virtualization overheads. That is, having the networking or storage go through any hypervisor software layer is…

[deleted]

Re: SSDs have become fast, except in the cloud

#236

Post by ddorian43 »

hathawsh wrote: post #201
pclmulqdq wrote: post #42

Earlier quoted context omitted.

It's because the "local" SSDs are not actually physically attached and there's a network protocol in the way.

That seems like a big opportunity for other cloud providers. They could provide SSDs that are actually physically attached and boast (rightfully) that their SSDs are a lot faster, drawing away business from older cloud providers.

Next thing the other clouds will offer is cheaper bandwidth pricing, right?

Re: SSDs have become fast, except in the cloud

#237

Post by akira2501 »

kwillets wrote: post #155

AWS docs and blogs describe the Nitro SSD architecture, which is locally attached with custom firmware. > The Nitro Cards are physically connected to the system main board and its processors via PCIe, but are otherwise logically isolated from the system main board that runs customer workloads. https://docs.aws.amazon.com/whitepapers/latest/security-desi... > In order to make the [SSD] devices last as long as possible…

I've noticed the firmware programming positions have been more common in their job listings lately.

Re: SSDs have become fast, except in the cloud

#238

Post by dekhn »

adgjlsfhk1 wrote: post #232
dekhn wrote: post #205

Earlier quoted context omitted.

"Physically attached" has had a fairly well defined meaning and i don't normally expect a cloud provider to play word salad to convince me a network drive is locally attached (like I said, if true, I would need to have a chat with my TAM about it). Physically attached for servers, for the past 20+ years, has meant a direct electrical connection to a host bus (such as the PCI bus attached to the front-side bus). I'd l…

Ethernet cables are physical...

The NIC is attached to the host bus through the north bridge. But other hosts on the same ethernetwork are not considered to be "local". We dont need to get crazy about teh semantics to know that when a cloud provider says an SSD is locally attached, that it's closer than an ethernetwork away.

Re: SSDs have become fast, except in the cloud

#239

Post by silverquiet »

treflop wrote: post #193
silverquiet wrote: post #78

Earlier quoted context omitted.

> Literally depending on where things are in a data center I thought cloud was supposed to abstract this away? That's a bit of a sarcastic question from a long-time cloud skeptic, but... wasn't it?

Cloud makes provisioning more servers quicker because you are paying someone to basically have a bunch of servers ready to go right away with an API call instead of a phone call, maintained by a team that isn’t yours, with economies of scale working for the provider. Cloud does not do anything else. None of these latency/speed problems are cloud-specific. If you have on-premise servers and you are storing your data o…

Oh, I'm not a complete neophyte (in what seems like a different life now, I worked for a big hosting provider actually), I was just surprised that there was a big penalty for cross-VPC traffic implied by the parent poster.

Re: SSDs have become fast, except in the cloud

#240

Post by Ericson2314 »

Nextgrid wrote: post #51
ejb999 wrote: post #19

Earlier quoted context omitted.

How much faster would the network need to get, in order to meet (or at least approach) the speed of a local SSD? are we talking about needing to 2x or 3x the speed, or by factors of hundreds or thousands?

The problem isn't necessarily speed, it's random access latency. What makes SSDs fast and "magical" is their low random-access latency compared to a spinning disk. The sequential-access read speed is merely a bonus. Networked storage negates that significantly, absolutely killing performance for certain applications. You could have a 100Gbps network and it still won't match a direct-attached SSD in terms of latency (…

Um... why the hell does the network care whether I am doing random or sequential access? Your left that part out of your argument.
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