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DDRamDisk: RAM disk, a disk based on RAM memory chips

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Re: DDRamDisk: RAM disk, a disk based on RAM memory chips

#81

Post by arnejenssen »

arnejenssen wrote: post #9

When doing my PhD around 2004 I was running simulations with Fortran programs to do optimizations. A genetic algorithm would call the Fortran program and change the parameters by creating input files and reading output files. I found out that disk access was the bottleneck of the optimisations. So I used a RAM disk software to create a disk-drive in RAM. It increased the simulation speed by orders of magnitude.

Some years later (2015?) I tried to speed up the build of JavaScript projects by moving my dev-folder to a RAM-disk, but it didn't really move the needle. So disk-IO is not the limiting factor when building.

Re: DDRamDisk: RAM disk, a disk based on RAM memory chips

#82

Post by inasio »

loxias wrote: post #76

If only Intel hadn't cancelled Pmem. Insanely high speed, density to match NVMe, could have changed the way we use computers (or at least powered some killer DB servers)

Are you talking about Optane/3D-XPoint? The physics behind it seemed insane to me, amazing that they got it to work. I heard that the NVME protocol was originally designed with it in mind

Re: DDRamDisk: RAM disk, a disk based on RAM memory chips

#83

Post by TonyBagODonuts »

cronix wrote: post #67

I remember doing something similar in windows 3.1 back around 90-91. Hard disks weren't quite fast enough to play very good video (I was using 3D Studio back then and IIRC this was still owned by Autodesk then as a spinoff product of Autocad) so you made a ramdisk and played the video from that. Only a few seconds at 640x480x256(colors) though. I think I had 4 Megs of ram in that 486 machine.

I believe it was Discrete Logic out of Chicago that made 3d studio before the tragic buyout by autodesk.

Re: DDRamDisk: RAM disk, a disk based on RAM memory chips

#84

Post by notyourday »

Around 1995(?) Erol's Internet used a static RAM based ram-drive device to process email for its tens (hundreds?) of thousands of users. Its larger brother was used to handle Usenet. Unfortunately the Usenet feed was growing like crazy and soon that large drive could not handle it.

... In 2010 some slightly nutty young engineers who heard about that story from the grey beards they worked with at a future very well known company on a very large mysql instance used a monster ramdisk as a single master to achieve a crazy boost in performance. The hard data persistence was achieved via replication to the regular spinning rust slaves. While it worked really well for their application no one ever battle tested bad crashes in production...

... that led to a product around 2013(?)-2014(?) from Violin Memory which combined the ramdisk with if I recall correctly spinning disks to dump the data in case of a power loss. The devices were absolutely amazing but did not create a foot hold in the market. I think they sold a few hundred units total. The product was abandoned in favor of flash arrays

Re: DDRamDisk: RAM disk, a disk based on RAM memory chips

#85

Post by nebula8804 »

notyourday wrote: post #84

Around 1995(?) Erol's Internet used a static RAM based ram-drive device to process email for its tens (hundreds?) of thousands of users. Its larger brother was used to handle Usenet. Unfortunately the Usenet feed was growing like crazy and soon that large drive could not handle it. ... In 2010 some slightly nutty young engineers who heard about that story from the grey beards they worked with at a future very well kn…

OMG Erol's internet was my first ISP as a kid in elementary school here in NJ. It provided my first experiences into the web and I remember it fondly because of that.

One of the first tech based mistakes I ever made was to convince my parents to switch from Erols(which had decent ping times on online gaming) to AOL (which had horrendously bad ping times) all because I thought I was missing out on the exclusive content that AOL provided. I do recall fun memories living in AOL's walled garden but giving up that ping time was horrendously bad. I once ripped out the phone wire from the jack in extreme frustration (first time tech made me angry lol!)

We eventually switched to Earthlink(and then I think Juno?) once the AOL 1 year contract was up. Excellent ping times but man Erols will always have that spot in my memories.

I miss all the excitement and innovation happening back then. I wish we still had mom and pop stores providing things like internet services. Even startups today don't feel like they could be done as simple "mom n pop" enterprises although im sure there are plenty hiding in places we dont often look.

Re: DDRamDisk: RAM disk, a disk based on RAM memory chips

#86

Post by semi-extrinsic »

rwmj wrote: post #12
nubinetwork wrote: post #8

Earlier quoted context omitted.

Even older... https://silentpcreview.com/review-blast-off-with-cenateks-ro...

The concept is old as the hills, if you include static RAM. It was a common way for early digital synthesizers (early 80s) to store patches in battery backed SRAM. Even on removable cards.

The original GameBoy cartridges often used battery backed SRAM for savegames.

Re: DDRamDisk: RAM disk, a disk based on RAM memory chips

#87

Post by wmf »

guenthert wrote: post #77

Uh, in which case is that supposed to fit? From the pictures it looks like its a few inches too tall (not flush with bracket). I seem to be missing something obvious.

Graphics cards are also that tall, so I guess this will fit in a gaming PC.

Re: DDRamDisk: RAM disk, a disk based on RAM memory chips

#88

Post by semi-extrinsic »

arnejenssen wrote: post #81
arnejenssen wrote: post #9

When doing my PhD around 2004 I was running simulations with Fortran programs to do optimizations. A genetic algorithm would call the Fortran program and change the parameters by creating input files and reading output files. I found out that disk access was the bottleneck of the optimisations. So I used a RAM disk software to create a disk-drive in RAM. It increased the simulation speed by orders of magnitude.

Some years later (2015?) I tried to speed up the build of JavaScript projects by moving my dev-folder to a RAM-disk, but it didn't really move the needle. So disk-IO is not the limiting factor when building.

Or your OS started caching the filesystem more agressively to RAM, so any piece of code that does heavy IO is effectively put on a RAM-disk automatically.

Re: DDRamDisk: RAM disk, a disk based on RAM memory chips

#89

Post by Felger »

Dylan16807 wrote: post #62
Felger wrote: post #7

Earlier quoted context omitted.

A very useful use case discovered no later than last week : local dedup management by Synology C2 Backup Agent and TBW on the OS SSD. C2 Backup agent stores dedup/chunks data by default in ProgramData, which is stored on C:... which is usually a SSD nowadays. I noticed a 3:4 ratio between written data in local dedup folder vs uploaded data volume on the remote C2 5 TB storage (suscribed a C2 Business). TBW grew indee…

I think the question was more tuned to physical ram disks, but I'm not sure. Either way, how many terabytes were being written each day? And how much can your drive take? It looks like I could go pay $60 right now for 600TB of endurance, and $35 for 200TB of endurance. If you already have the extra ram than go for it but it doesn't seem like a setup to make on purpose. Maybe your backup system has far more writes tha…

(I was answering to the previous comment wondering if ramdisks still have any interesting usage nowadays.)

About 150 TBW endurance on a 250 GB Samsung M.2 NVMe Evo 970+. On paper that is, but since it is the OS SSD with Windows Server 2022 STD (sole DC AD/DHCP/DNS/Hyper-V), in production, I won't take any risk. RAID 1 in this scenario would have changed nothing. On the side, I have 40 TB RAID10 for storage.

So I cancelled the first C2 exec (with C2 encrypt on) when I reached 195 TBW on the SSD. Monitoring the ramdisk use still shows about 3:4 ratio on complete snapshot.

I have about 1 million files on the 2,29 TB data to backup.

I had indeed the RAM sticks available for free, simply had to take them (2x16 GB ) from a decomissioned ML350 Gen9 (which uses DDR4-2133P ECC Reg). It now serves me as a bench, litterally.

Re: DDRamDisk: RAM disk, a disk based on RAM memory chips

#90

Post by outworlder »

JonChesterfield wrote: post #54

An interesting quirk of the later designs is they're bring your own ram. That might be a worthwhile thing to do with a pile of DDR3 from an old server. I think I've got 256gb or so in a draw somewhere that's otherwise unlikely to see any use. Lithium battery strapped to consumer chips - so you can basically ignore the volatility aspect (possibly in exchange for an exciting new fire risk, not sure how professionally b…

> Lithium battery strapped to consumer chips - so you can basically ignore the volatility aspect (possibly in exchange for an exciting new fire risk, not sure how professionally built these things are)

Do LiFePO4 instead. Nothing is fireproof but those are pretty tame.

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