Good point about the fact that there's not actually an official number of unconfirmed tx on the network.  I understand.  However, I can look at http://blockchain.info/unconfirmed-transactions and see that there are currently more than 19K transactions waiting for confirmation according to one particular node.  When I looked at this page anytime in the past few years it tended to be between 500 and 1500 unconfirmed transactions, so the change is an order of magnitude. I think that kind of scale overcomes any sort of difference between nodes.   Ie, it's not the case that bci has 19K unconfirmed tx and antpool has 500.  The same page shows that transactions are being sent at approx 0.8 per second.  These numbers are simply much higher than they were a month ago.  Something is happening.  I'm just trying to figure out what.

The nodes that blockchain.info uses may have different rules then what other nodes may use. If you look at blockchain.info's rejected inventory you will see that it is rejecting a large number of transactions that are including fees that are less then what many other nodes will relay by default. When those transactions are not yet confirmed and a new transaction that relies on at least one of those outputs then blockchain.info will think the transaction is invalid when it is not.

My node is showing 42k unconfirmed transactions that will take up 132 MB worth of block space. This is probably a more accurate representation of the unconfirmed transactions out there.

You should really not rely on blockchain.info for this kind of information because they have a long history of getting things incorrect.

They are also incorrect regarding the number of transactions per second. A much better source, http://statoshi.info/dashboard/db/transactions is reporting between 1 and 2 transactions per second right now, this is probably more accurate. The overall best way to get information about the current state of the network is to get it from bitcoind that is running on your full node. If you are lucky, you can rent a VPS for only a few dollars per month with high enough specs to support running bitcoind, if you are not lucky then you can rent one for only ~$10 per month.

Post or PM me the txid and I will see if I can help you out

I think the Chinese are behind the current transaction volume and one of the reasons would be that their government has banned major stock holders to sell  stocks for the next 6 months, some may have adapted to Bitcoin as these rules kicked in.

I dont think anyone is willing to burn that kind of money just to "test" the network. The networks behavior was pretty clear during the first tests. There was a LTC pump and dump recently and now BTC crashed from 300. This might not be related to the attack though.

This dwarfs the first stress tests and is significantly longer in duration. My node currently sees somewhere between 42k and 60k unconfirmed TX. My node at home is running 0.11. and witnessed ~27k TX (~80MB) over night. I did however change it to accept any fee (as low as 1 satoshi) and plenty of free TX in order to make sure I get all of the spam.

Blockchain.info however modified their nodes to not accept most of the spam TX, which would explain why they show such a "low" number.

May i ask where did you get that chart from, thank for it also i havent been able to find something like that to see a 30 day perceptive of the transaction volume progress, I do also wonder how long would they or he could keep up that high volume of transactions is most likely to be a large operator to run that type of volume.

yesterday = 0,00015 BTC of fees = no problem.

I am surprised that any nodes were still relaying the transaction after that long, especially if you are not running a full node that is rebroadcasting the transaction. May I ask which pool still had the transaction in their mempool when they confirmed it?

some unpredictable things would happen? the one thing is that price is raising to $300. anyway, this is a good sign

But the price "hike" you're talking about is from 250USD to like 300USD.  This hardly seems like a huge factor given that btc was at an all time high of like 1500USD and was over 500USD only like 8 months ago.  I have a hard time believing all these transactions are from legitimate trading volume.Yes, it seems there is some spam attack happening.  I'm personally quite surprised that it can be pulled off this long, someone must be spending a lot of money on this.  And why?  That's what I havent' figured out.Yes, this was already discussed upthread (it's really not a long thread, it's important to read before replying, especially when you're wearing a signature advertisement).