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I have a Dell-branded EMC AX150i disk array that refuses to enable its write cache. After calling Dell support, it turns out that the system will refuse to enable its write cache unless an APC SmartUPS is connected to the system.

However, the AX150 is in a data center and the data center won't allow UPSes to be installed in a customer cabinet; that is, to be attached to their UPSes. (I'm not an electrical engineer, but there's something about UPSes confusing the main DC UPS to think that there's a power fault.)

So I need to know if there is a way to force-enable the write cache on an AX150. (The Dell tech says no.)

Failing that, does anyone know of a SmartUPS communication emulator that I can use to fake the AX150 into thinking that there's a UPS there?

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FWIW, the data center is installing an unprotected power circuit for us to attach the UPS to. – wfaulk Feb 11 '12 at 15:22
up vote 2 down vote accepted

For anyone that is still looking for a program to Emulate the APC SmartUPS for the AX150. Here is a link to one that is done in C#. You will need .Net installed on you system to run this (4.0 it may work with 3.5). I have it running on my system right now and it has allowed for Write Caching to be enabled without the UPS. The program is based on Serial Comm program found here (

The program i am using can be found @

I will be making some changes to it as the program right now has alot more to it then needed, but for right now it does work. (do not use the HEX option as it has not been finished.)

If you would like the source for this let me know.

jon dot slaterhouse at gmail dot com

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You can try to build your own, but I don't think there's a way to force the machine to act like there was a UPS enabled.

If this costs more than 10,000$ of your time, you might be better off buying a low end replacement for the AX150 that doesn't try to force you to connect a small UPS when you have a large one feeding the whole rack.

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