HDD RAM concept

[joeleg]

So I was wondering what would happen if a lot of HDDs were connected in a RAID 0 and were to be used as RAM for a computer. A RAID 0 should increase the read/write speeds of the drives so it should be able to match some DDR3 speeds with about 50 drives. I know it is ridiculous overkill but in concept would it work? would a software or hardware RAID be needed? I think it would need to be connected with multiple thunderbolt 3 cables to start to match RAM speeds. This is my first post, so I hope i'm doing it in the right place.

[minibois]

It can probably be done, but it's just something that doesn't make sense.

Also, you need like 250 average drives to match DDR3 1866 memory speeds. Those king of numbers don't make it worth it, in a world where 128GB of RAM is (right now) a lot.

[ProjectBox153]

That wouldn't be very practical if it even could be done. The drives would fail and then your current OS session would be dead. 

[LUUD18]

You still have the random read delay. So it will never be as fast as ram.

[grimreeper132]

would it work probably, to a point of the difference would be nearly unnoticeable, is it worth it, no, no point

[Oshino Shinobu]

Latency would be the major issue. HDDs are much, much slower than RAM in terms of access times and putting an additional RAID controller inbetween that makes it even worse. 

[grimreeper132]

3 minutes ago, Oshino Shinobu said:

Latency would be the major issue. HDDs are much, much slower than RAM in terms of access times and putting an additional RAID controller inbetween that makes it even worse. 

you could get it to a point where the difference is nearly unnoticeable, e.g. the difference from accessing from RAM is 8us and hard drive raid array 20us (u is the micro symbol, can't be bothered getting the fancy u it's meant to be) it's still slower and the HDD will still need to go through RAM however making it 28us so it'll be slower, but unnoticeably slower to a human.

[ProjectBox153]

Just now, grimreeper132 said:

you could get it to a point where the difference is nearly unnoticeable, e.g. the difference from accessing from RAM is 8us and hard drive raid array 20us (u is the micro symbol, can't be bothered getting the fancy u it's meant to be) it's still slower and the HDD will still need to go through RAM however making it 28us so it'll be slower, but unnoticeably slower to a human.

It would be really hard to get it that low. The latency with drives reading and writing is way higher than flash memory. Maybe with SSDs, but I'm not sure. 

[porina]

4 minutes ago, grimreeper132 said:

you could get it to a point where the difference is nearly unnoticeable, e.g. the difference from accessing from RAM is 8us and hard drive raid array 20us (u is the micro symbol, can't be bothered getting the fancy u it's meant to be) it's still slower and the HDD will still need to go through RAM however making it 28us so it'll be slower, but unnoticeably slower to a human.

Where are those values from? Latency for ram is 100ns ball park magnitude, latency for even a high rpm HD will be in the ms range if not already cached in ram either on drive or controller. That's many orders of magnitude between them.

[Guest]

1 hour ago, joeleg said:

So I was wondering what would happen if a lot of HDDs were connected in a RAID 0 and were to be used as RAM for a computer. A RAID 0 should increase the read/write speeds of the drives so it should be able to match some DDR3 speeds with about 50 drives. I know it is ridiculous overkill but in concept would it work? would a software or hardware RAID be needed? I think it would need to be connected with multiple thunderbolt 3 cables to start to match RAM speeds. This is my first post, so I hope i'm doing it in the right place.

Night theme matters...

 

1 hour ago, joeleg said:

So I was wondering what would happen if a lot of HDDs were connected in a RAID 0 and were to be used as RAM for a computer. A RAID 0 should increase the read/write speeds of the drives so it should be able to match some DDR3 speeds with about 50 drives. I know it is ridiculous overkill but in concept would it work? would a software or hardware RAID be needed? I think it would need to be connected with multiple thunderbolt 3 cables to start to match RAM speeds. This is my first post, so I hope i'm doing it in the right place.

I would still not think it would be RAM speeds...

[ProjectBox153]

1 minute ago, Factory OC said:

Night theme matters...

I've just stopped using Night Theme when I see posts like this. 

[Guest]

Just now, Jamiec1130 said:

I've just stopped using Night Theme when I see posts like this. 

My eyes can't take it...

[grimreeper132]

2 hours ago, porina said:

Where are those values from? Latency for ram is 100ns ball park magnitude, latency for even a high rpm HD will be in the ms range if not already cached in ram either on drive or controller. That's many orders of magnitude between them.

made up values that sounded about right for how much bigger the magnitude for the HDD will be