If we are going to mince words I was somewhat incorrect in the initial phrasing, which I clarified later. I clarified that I regularly get messages like "exchange A will not be able to trade products A to J". I did not say hours at a time, and I do see these messages very very often. The reason is because with IB I am subscribed to about 30 exchanges. Thus the probability that an exchange will have problems is pretty high.
And it is no BS regarding the problems with the exchanges. Everybody assumes that exchanges just work and you will never have problems.
Take a look at the following:
http://batstrading.com/alerts/
See all of the alerts and the problems? Now imagine being subscribed to 30 exchanges? I see lots of messages, and it is a bit annoying because IB keeps pinging.. I am not even including the market data issues, which are quite common as well.
As was said previously 95% of the time it does not affect you. But sometimes it does affect you. And if your algorithm or trading style assumes no exchange problems then you are asking for trouble.
I used to run a trading algorithm that traded based on second increments, and keeping the runtime data clean was a HUGE problem. In the end what I ended up doing was getting every 15 minutes a historical tick data refresh. Otherwise I would have skew where I would miss trades or enter a trade on bad data.
The problem was not that I overfitted my algo, but when the market moves fast data might come to fast or too slow. My point is that if you are trying to minimize round trip time, or keeping the system running without having a running system you are wasting your time.
The hardest part with a 24x7 trading system is making it robust to deal with a noisy market data... If you figure that out you will make money...
Christian
Quote from ScoobyStoo:
As has already been pointed out by Aitch Eff Tee, this is very very different to an exchange or product going offline. You are talking about liquidity issues.
No it is not the same thing. From your perspective they might have the same impact on your trading strategy but you can't expect to post a comment saying that you see exchanges going offline for hours every day without someone calling it out as bullshit. What you said was factually incorrect.
The SPX has been a joke for a long time. Most the volume is institutional and done off exchange. The CBOE screwed up with this instrument many years ago by not allowing any competition. Depending on your trading needs you might find the SPY options a better bet...
Best of luck.