>>Would this help http://support.microsoft.com/kb/297684 ?
>
>Thanks, but in our case, this has worked for years and suddenly started to act like this. Also, there are constant traffic between both servers. Also, the article suggests to simply do nothing as any request to it would reconnect the drive. In our case, the drive cannot reconnect. I have to attempt several times until it does. This is why I suspect hardware problem.

In 22+ years of computer support, I've seen a network cable "go bad" exactly once. I suspect, in that case, it was a marginal cable to begin with, and one of its connections degraded to the point where the cable didn't work at all any further.

With cables, more common failures are:

- someone trips on one. This may or may not yank the cable out of the wall jack/switch or the back of the computer, damage the wall jack/switch/NIC on the computer, damage the connector(s) on the end(s) of the cable or break one or more wires in the cable itself

- someone pushes furniture up against a wall, crushing a cable end/connector and/or damaging the wall jack

- someone steps on a cable on the floor, or rolls over it with the wheels of a desk chair, crushing or breaking individual wires within the cable

- the prong on an RJ45 connector gets broken off, so the connector no longer locks securely into the jack, and works loose over time

Servers these days typically have gigabit or faster NICs. Although Cat5e cabling is nominally good enough for gigabit (note that plain Cat5 is NOT), really you should be using Cat6. I'd also be concerned that cheap Cat5e cables may not actually meet the spec, network cable can be prone to counterfeiting.

So, one quick thing to try would be a good-quality Cat6 cable. You could also try plugging the cable into a different port on the switch, I have on a few occasions seen an individual switch port go bad (although, far more often, the switch itself is failing or has failed).

Sometimes connectors get loose over time, or build up some oxidation that makes for a bad contact. You might find that simply unplugging, then plugging the cable back in can scrape off oxidation and create a new, tight connection and that may fix the problem. If you're feeling ambitious, you could use some contact cleaner. I worked for a few years in an industrial plant, one of the most useful things I took away from that experience is that something like 80% of electrical problems of any kind are caused by bad contacts.

There are other things that could cause dropped connections:

- Windows power schemes, even for servers, often allow the computer's NICs to be powered down to save juice. Check to see that this feature is disabled for all your computers e.g. Device Manager...Network Adapter...Properties...Power Management: "Allow the computer to turn off this device to save power" should be un-checked.

- Some network switches have "green" power-saving features that will power down ports that don't seem to be in use. That feature saves pennies per year at best and should be disabled

- Don't use devices that need Power over Ethernet (PoE) unless the switch they're attached to explicitly supports it. Doing so could affect the whole switch

- If you're running an antivirus suite that includes a firewall, you could try temporarily disabling the firewall to see if that has any effect