RAM Is the New Disk
medium.com
RAM Is the New Disk
1–10 of 74 posts
Re: RAM Is the New Disk
#2Are you sure latency stayed around 100ns?
http://pics.crucial.com/wcsstore/CrucialSAS/images/campaigns...
Re: RAM Is the New Disk
#3Are you sure latency stayed around 100ns? http://pics.crucial.com/wcsstore/CrucialSAS/images/campaigns...
Probably not but I think the point stands that latency hasn't made any major strides since the switch from SDR to DDR.
Re: RAM Is the New Disk
#4Are you sure latency stayed around 100ns? http://pics.crucial.com/wcsstore/CrucialSAS/images/campaigns...
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Re: RAM Is the New Disk
#5...
I was the third engineer at VoltDB and spent six years making that bet. It's not a good bet.
Maybe there are other factors, but if VoltDB could page out cold data to disk I think it would be at least 2x if not more successful. No one agreed with me so it never happened.
I saw so many use cases go out the door because hey you know what? RAM is expensive and it's cheaper to page out cold data. The scale where that cost starts to matter is not that big.
Re: RAM Is the New Disk
#6Are you sure latency stayed around 100ns? http://pics.crucial.com/wcsstore/CrucialSAS/images/campaigns...
That's very interesting. The estimate of 100ns came from here: https://people.eecs.berkeley.edu/~rcs/research/interactive_l.... and is probably not very precise (maybe because it is only capturing rough order of magnitude). I have now updated the post. Thanks for the feedback! Specific constant aside, the point about latency not improving much still holds.
Re: RAM Is the New Disk
#7Well yes, I think RAM has been the new disk for awhile now, and not because (anecdote about database disk structures) or (any recent change to cost of RAM).
If you use Linux, the fastest way to test how much faster your application is off disk is to simply make a filesystem in RAM, and run the whole thing from there. Because library-chasing to build a chroot is a hassle, I would recommend simply putting a container on a RAM-backed block device, then installing your application on the container.
I have personally designed, built and managed large clusters of diskless machines and find that the mix of RAM-only and PXE[1] boot is an excellent one for maintaining state (and security) across well managed infrastructure. Disks be damned. For permanent storage, consider sharing a DRBD[2] cluster from dedicated nodes.
[1] https://en.wikipedia.org/wiki/Preboot_Execution_Environment
Re: RAM Is the New Disk
#8> If anything, I would suspect that the developers have become costlier over time, at least in the last 10 years or so.
Really? Have developer costs actually increased in real terms in the last 10 years? Have your developer costs (if you're outside the VC/SV bubble) increased in real terms? And how much?
This seems like a terrible assumption.
Re: RAM Is the New Disk
#9> If anything, I would suspect that the developers have become costlier over time, at least in the last 10 years or so. Really? Have developer costs actually increased in real terms in the last 10 years? Have your developer costs (if you're outside the VC/SV bubble) increased in real terms? And how much? This seems like a terrible assumption.
The real point is that developer time has not kept up with the rate of RAM price decrease, and unless you plan on seriously defending the claim that developers only cost 1/6000th of what they used to twenty years ago, the points in the blog post stand.
Re: RAM Is the New Disk
#10... I was the third engineer at VoltDB and spent six years making that bet. It's not a good bet. Maybe there are other factors, but if VoltDB could page out cold data to disk I think it would be at least 2x if not more successful. No one agreed with me so it never happened. I saw so many use cases go out the door because hey you know what? RAM is expensive and it's cheaper to page out cold data. The scale where that…
Curious - why did people not agree with you? Was it an ideological belief or were they betting on some assumptions that turned out to be incorrect?