RAID Array & Controller Information | RAID Info | TechMikeNY



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Our Top 5 RAID Questions (Frequent or Interesting) Answered


RAID: The magical configuration of physical drives into virtual disks that allow for speed and redundancy.  Because RAID is such a large part of enterprise servers, at TechMikeNY, we field questions on RAID controllers and configurations daily. 

In this blog post, we'll share some of the common questions we get about RAID arrays and controllers and give you the information, as well as some unique questions that we thought were interesting.


"Hi, Mike.  I have installed an H810 PCIe RAID controller with my Dell R720 8-bay server.  But the system isn't recognizing the hard drives in the backplane.  Where did I go wrong?"


The H810 PCIe RAID card is for external use ONLY, such as connecting your server to a multi-drive enclosure. You will need an internal RAID controller to use the drives installed in the server's backplane.

We list this controller as "external" in our product descriptions.  Additionally, if you were to select this controller through our Configure-to-order tool, a rep would typically reach out to confirm that you, our customer, are aware that this is strictly an external controller.


Hey Mike!  I want to increase the size of my RAID 5 drive array, and I believe I can do this one drive at a time, so after the last drive in the array is updated, the total disk space would be increased.  Is this right?


In theory, this could work, but it would be incredibly time-consuming, not to mention risky, as there would be no fault tolerance in place during the process of replacing each drive one at a time. 

The Best Practice would be to make a full backup of the RAID 5 array, remove the old drives, install new drives, set up a new array, and then do a full restore.  You can read our blog post here on transferring RAID arrays between servers here.


Hi Mike, I love your site and the configure-to-order where you can play around with different specs! I was just curious if anyone has tried the Dell HBA330 in an R520? The price looks good, and I like the idea of keeping my PCI slots open. 


Thanks for the compliments on our Configure-to-Order page. A lot of development work went into it! 

As for your question on the HBA330 in a Dell R520, we have not had any customers try this. However, there are a couple of issues to be aware of:

  1. It would require a different set of cables. The 12th and 13th generation SAS connectors are different – specifically, 12th Gen takes cable SFF-8087; and 13th Gen takes SFF-8643.
  2. The mini-port where the RAID controller connects on the 12th Gen servers is different from the 13th Gen servers, so you need to use a PCI version anyway.

    We have had customers use PCI 12Gbps RAID controllers on R720 and R820 servers. However, they had to purchase the different SAS cables to convert the older connection to the newer 12Gbps connectors. I'm not sure if the R520 would support it. 

    See the photo below so you can see the different connectors between the 12th and 13th Gen servers. 


    Hi Mike.  The PERC battery in my R620 is indicating failure.  How can I fix this?  Do you sell replacements?  


    Since your R620 is within our warranty period, we'll send out a replacement RAID battery.  Please be very careful with the blue plastic clips that secure the RAID controller when installing the new battery.  You can view a video of one of our techs carefully removing the RAID controller on a 12th Generation here

    For future reference, 10th and 11th Gen Dell RAID controllers take this battery.  12th Gen Dell servers this take one, and 13th and 14th Gen controllers take this battery

     IN CASE YOU WERE WONDERING…  RAID controllers come with a dedicated battery to preserve the controller's cache memory in the event of sudden power loss.  A reliable power supply to the controller makes it easier to restore – or transfer – an existing RAID disk.  The battery also improves the controller's performance in that it allows it to store cache – which speeds up data transfers. 


    Mike.  Please help.  I have a Dell PowerEdge R815 server with 6 SAS disks on RAID 5 configuration. The RAID Controller is PERC H700. My server is dead due to a mainboard issue.   I want to recover the data on the disks. What's the easiest solution to recover the data without buying a new mainboard?  Is it possible to install this raid card on the Dell OptiPlex desktop system and connect disks to it and boot from there? 


    Sorry to hear about the system board failure.  If the RAID controller mounts into the dedicated slot on the server, then there is a good chance it will not work when plugged into a standard PCI slot on the desktop. These controllers are programmed differently if they are the PCI version or the dedicated port version and are not necessarily interchangeable between different systems, even of the same manufacturer. 

    If the above works, then it could be possible to leave the drives powered up in the PowerEdge server and then connect the SAS cables from the moved RAID controller in the desktop to the server's backplane.

    A much safer and reliable method would be to replace the system board or an entire R815 barebones chassis with a system board then move your RAID to that new chassis. 

    Do you have more questions on RAID that you don’t see answered here?  Never hesitate to reach out to us!  Leave a comment below or email us at  We love hearing from you!


    • Hey Rafael,

      Most likely, the RAID controller is the issue; however, it is also possible that the systemboard or drive backplane may be having a problem. The only thing you can really do is to try replacing the RAID controller and see if that resolves the issue. You can find it at the following link:

      Hope that helps!

    • Hi, Mike I have a poweredge t420. it got water about a month ago and the H720p got wet., at the beginning the server will not turn on, today it turn on and stops by saying no boot device available..the hard drives have no ligth. How can I know if thre problem is the raid controller h710p, or the hard drives ( the hard drives I think did not got wet), Thanks

      Rafael Gottenger

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