Yet another cheapo 4GB Ram listing...

Sleyk

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BackupProphet

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Expensive! Last batch I got, I paid $1.5 per stick :)
So I bought 500 sticks for 750 USD, that is 2TB ram :p

It was 8500R though, had to pay slightly above $2 for 300 sticks of 10600R. But for cache servers like Redis/Varnish 8500R is just fine.

But enough bragging, I strongly recommend bidding on 4GB memory lot auctions. I've not seen one auction for the last 3 months where you had to pay more than $3 per stick. If you just need a few modules then I guess this deal can be considered good.
 

Boddy

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Hi @BackupProphet I'm interested in your cache server set up. A dual socket motherboards like Intel S26000CP2J have 16 x ram slots. At 4GB per slot that equates to 64GB ram. Are you using any special motherboards for your cache servers or can you set up multiple servers to act as one big cache? Cheers
 

BackupProphet

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I use multiple servers with data sharding. Which means I calculate a hash/number (xxhash 64-bit toLongValue ) for each object which I then use a simple modulo function to calculate which shard it should be stored in. In that way I have efficient distributed caching. Keep in mind that if you have many billions of objects, you may need a larger number than xxhash 64-bit to avoid collisions.

So in practice this means that if someone is accessing image /category/hardware/memory/hynix-4gb-ecc-pc3-10600-registered on my website, that url will generate the following long value 3878264635277911309.

If I have 4 shards/servers, I use the modulo function to figure out which shard it can find the object. For example 3878264635277911306 % 4 == 2. So the data can be found on shard 2.

That is how I do it, it's no more fancy than this :)
 
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Boddy

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Thanks so much @BackupProphet for your insightful feedback! Very interesting. Special thanks to Google my friend for getting my head around some of this stuff) So, it appears there is a xxhash version to suit various platforms? Does long Value available for several platforms as well? Then you apply modulo function. Am I understanding correctly?

For a novice, it does sound time consuming though. Do you have a script that does xxhash+Long Value+mondo function automatically?
Plus do you need to do the calculations for each object individually or can group of objects be done simultaneously? Such as if you had hundreds of objects.

Caching to RAM and data sharding certainly makes me reconsider hosting set up and makes my goals much more achievable. Thanks for that!
I'm guessing for caching and data sharding you do not need high end gear, eg dual Xeon 56xx would do (is it better going for 6 core CPUs over 4 cores)? What bandwidth NICs are you using between data shard computers and the master server? Cheers.
 

BackupProphet

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XXHash is a commonly used hashing library that is available on most common platforms and programming languages. You can use a lot of other hashing libraries too, they each have their pro and cons. XXHash's strengths are speed and good randomness while still just being 64 bits.

A hash function will create a byte array which then can be converted to a number. It is not time consuming at all, but programming knowledge is required. I do calculations at runtime, as it is very fast to do them.

You do not need high end gear, that's the point when they say consumer-grade hardware. In most cases 1 single core is plenty to push 10G of traffic. Redis does like 500k-2mill requests on a single core. And Varnish uses around 50% cpu when pushing 10G of traffic. Even high traffic sites like Stack Overflow does not need that kind of performance.

I do use 10G today as it is basically free, but that is mostly for the reduced latency. Latency matters more than throughput.

Sorry for thread hijack.
 
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Fritz

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Thanks, just bought a dozen of them for a future project.
 
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Boddy

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Thanks once again @BackupProphet for the information, it certainly is useful and intriguing and another way to set up hosting without high end gear. And sorry to all for hijacking the thread, it's my fault.
(Least it could be seen as an inspiration to buy a truck load of cheap ram. :))
 
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T_Minus

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Expensive! Last batch I got, I paid $1.5 per stick :)
So I bought 500 sticks for 750 USD, that is 2TB ram :p

It was 8500R though, had to pay slightly above $2 for 300 sticks of 10600R. But for cache servers like Redis/Varnish 8500R is just fine.

But enough bragging, I strongly recommend bidding on 4GB memory lot auctions. I've not seen one auction for the last 3 months where you had to pay more than $3 per stick. If you just need a few modules then I guess this deal can be considered good.
I can't wrap my head around how min. 2x servers all loaded with 4GB sticks is more affordable than half the servers with 8GB sticks.

Even if we assume $2 for 4GB and $10 for 8GB
- 4GB - $2 - 500 qty - $1000
- 8GB $10 - 250 qty - $2500

$1500 Difference

Reduction of min. 11 servers if we're sticking with 500 4GB sticks assuming all are 24 dimm capacity which would be unlikely it seems if you're bargain hunting.

10 servers excluding RAM easily makes up $1500 let alone the power-usage... heck even 10x 1366 1U chassis is pushing it but I guess yields the 24x dimms on the real cheap up front cost, and screws-ya on the power usage.

How are you justifying 4GB at $1.5 to $2/stick when 8GB yields at-least 50% reduction in build-cost and power utilization?

I can't make it make sense in my head unless power is dirt dirt cheap :D
 
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BackupProphet

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The way you're presenting it makes sense, but there are still a lot of details that makes it favorable to pick 4GB. I don't use them all for mem-storage purposes, and power is dirt cheap here, somwhere between 0.75c to 0.85c per kwh.
 
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T_Minus

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Don't get me wrong @BackupProphet I have a bunch of 4GB in use where I don't need much memory :) Just trying to see the math inhow it worked for ya ;)
 

Sleyk

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Sorry for thread hijack.
No worries my friend! It's always welcomed to have people discuss the benefits of ram, as it is always helpful to decide if something continues to be cost effective or if we should now seek another method of doing things. It was good to read alittle on ram use in cache servers.

Now, I personally still buy and go for 4GB sticks due to the sheer abundance. I think for an enterprise endeavor, My man TMinus makes a great point, most large server sets will go for higher density, and overall reduction in final/ongoing expenses, and in the longer run, density and power may hold sway, but for home use, I think 4GB sticks being as cheap and abundant as they are, is not a bad way to go. I especially enjoy the replacibility of the 4GB sticks if nothing else. If I burn a stick or two, it costs me less than 10 bucks to grab three more. Its just not so with 8GB sticks my friends.

I almost feel as if 4GB for home use, and 8GB for enterprise/professional use. That's silly, I know! But for home use, We can get away with as little as 8gigs of ram for freenas/nas4free and small servers. So a small server with 4-8 ram slots with 4GB sticks in each slot yields around 16-32 gigs. More than enough right guys? I got 24gigs of ram in 6 slots (6x4GB) in my small document/file server, and 48gigs (12x4GB) in my main servers. I gets no problems with this. You schmucks must be doing some serious virtualization and number crunching is all i see. Heheh.

I am a poor clown bastard guys! I needs me tech to be cheap and easy to find...
 

Sleyk

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Least it could be seen as an inspiration to buy a truck load of cheap ram
Yeah! But you know, I feels like I can beat ya in arm wrestling. I don't know why....:cool:

(I'm kidding, you will smash my twig of an arm to pieces.)
 

Boddy

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The way you're presenting it makes sense, but there are still a lot of details that makes it favorable to pick 4GB. I don't use them all for mem-storage purposes, and power is dirt cheap here, somwhere between 0.75c to 0.85c per kwh.
I'm curious what you would do with 2 TB of memory if not using them for mem-storage purposes.
My power is 0.35c per kwh and I consider it expensive after increasing 50% in last 4 years?
If you use much power during the day, would solar panels have some cost benefit at price you pay for electricity? I'm on a peak/off peak plan and it's 0.15c between 11pm-7am and weekends.
 

T_Minus

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I think there's some confusion on $ and c, assuming c = cent / ¢

$ .15 = 15 Cents

.15 c != 15 cents

At-least how I'm reading it / understanding the usage ???

So are you really paying 75 to 85 cent or < 10 cent?

I can't imagine paying almost $1 being cheap, but .75 cent or even 7.5 cent seems insanely cheap!!
 

Boddy

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Yeah! But you know, I feels like I can beat ya in arm wrestling. I don't know why....:cool:
I am not as I appear. PS. That's not a pic of me...lol
I just wanted to get away from concept that geeks should look a certain way.

PS. Don't believe that you are a poor clown bastard. Your heart is in the right place.
With such a kind heart, who knows you may aspire to become a bodhisattva and bask in high regard and admiration, such as the great Quan Yin. Best wishes. :)
 
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Boddy

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Sorry I meant $o.35 peak and $0.15 off peak. Sorry about that!
(I cannot imagine electricity being < 1 cent a kwh, that would really be cheap - a good place to open up a data centre. :D)
 
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T_Minus

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I ment c, and I live in country with great data center potential.

EDIT: Actually my bad, its not less than a 1c, but around 1.5-4c. During peak times (cold dry winter) it may spike up to 10c.

SO JEALOUS :D:D of that rate... OMG