Wednesday, May 27, 2015

Perc H700 Connector Confusion

Throwing this one out there in case anyone hits a similar issue. This one confused the heck out of me but was simple in the end.

We have a customer with a Dell T310 server with an H200 RAID adapter. The performance on the H200 is pretty poor. In part because the drive cache is disabled by default. But, search around and you'll see no one has much nice to say about the H200.

To improve performance for this server, we ordered an H700i card from Dell. We ordered from Dell rather than aftermarket to avoid issues with compatibility. And so that it would be supported.

There are several sets of instructions out there for doing this upgrade. Here is the one I thought was the best:
We went through the guide, installed the card, installed drivers, and then went to connect the drive backplane to the card. Uh oh, wrong connector type.

You can see above that the new card has a two prong connector that does not match the mini SAS connector (shown below) of the cables that shipped with the card. The cable already in the server also had this type of connector.

While I'm comfortable with server hardware, I'm by no means an expert on all different connection types. So, at this point I assume that there is a connector type that I'm unaware of and we need either a different card or different cables.

My rep confirmed that this is in fact the correct card. Next step is calling support. I sent the pictures to support and he wasn't sure what was up either. While on the phone as the support rep was searching, I tried searching for SAS connector types and nothing matched what I was seeing on the card. It wasn't making sense. This can't possibly be correct.

At this point, I tried gently pulling on the plastic part of the connector and it came out (see below). The plastic was a spacer put in the connector for shipping. After removing the plastic plug the connector fit the cable properly. It seems obvious in retrospect, but it didn't at the time.

One final note about this card. We ordered the model with 1 GB non-volatile RAM. I assumed that this meant no battery was required. In fact the card uses DRAM for operations because it is faster than NVRAM. The battery is still required to move data from DRAM to NVRAM when a power outage occurs.

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