Start a Conversation




8 Posts


May 3rd, 2023 11:00

Suggestions for adding drives to existing RAID-1 drive pool..?

Hi all.. I'm new here ..

We've got a 1 year old PowerEdge R350 and initially spec'd it with a pair of 1.92Tb SSD Sata drives (this model here).  We'd like to increase our storage pool from 1.92Tb to about 6-8Tb without breaking the bank so to speak.  

The server has 6 empty hot-swap 2.5" slots available (of the 8).  I don't know if there are any non-SSD drives that would work or just get more of the same drive to add..? 

If there are non-SSD drives available, is it a bad idea to mix SSD w/ non-SSD drives -- with or within the same virtual drive?

I just want to make sure I don't buy something I'll later regret. 

ps. Our system has a PERC H755 controller if that matters..

Thanks much!

16 Posts

May 5th, 2023 10:00

Hey Rick

No problem at all, let me explain from the images you sent what you have in your system. You have an 8 x 2.5-inch SAS/SATA (HDD/SSD) backplane, it’s what we refer to as a universal backplane, it can take either SAS/SATA mechanical drives or SAS/SATA SSD drives. You should have 6 slots that are currently populated with what we call blanking plates. The blanking plates are needed when physical disks aren’t in the slots for airflow reasons.

They should resemble something similar to the image below. You currently have 6 of these in the system. If you take one out and peer into the gap, you will see a connector which is on the physical backplane that a drive plugs into.




The connector itself is designed to accept both SATA / SAS drives. The connectors on the physical drives you purchase from Dell will seamlessly plug into the backplane and get detected by the PERC controller which is connected to the backplane via cables.


If you log onto your iDRAC 9 and click on the storage tab you will see something like the image below (depends on the iDRAC license and firmware).


Click on enclosure.



On the enclosure tab, scroll down to the bottom of the screen and it will list the available free slots, in this example the system has x8 backplane with 4 disks populated and 4 free slots. The disks highlighted in green are drives that are in a “ready” state, this means the disks are not currently part of a raid set/virtual disk.


When you populate your new disks into the backplane they will appear automatically (no need to reboot) as the backplane and drives are what we refer to as hot pluggable, and the new drives will appear in a ready state.




From the iDRAC GUI you can then configure the new drives into a raid set without rebooting the system by clicking on the “create virtual disk” tab.



A setup wizard will pop up – give the Virtual disk a name, select the raid layout and click next



Select the new disks and click next



Click next on the virtual disk settings



On the confirmation tab click next. It will then prompt you on the next screen to “apply now”. The process of creating the Virtual disk will start. After a few minutes you should see the new Virtual disk in the iDRAC storage tab, you will also see it in your operating system. Again, the system/operating system will not need to be rebooted



Just one other reminder. Make sure when you’re speaking to sales, to tell them you need 2.5inch drives. The R350 had a flexible option in terms of backplanes, you could buy them with a 3.5inch x 4 slot backplane or you could buy it with the 8x2.5inch backplane which you have.

Once there 2.5inch drives, it doesn’t matter what you choose, you can purchase SAS 10k/15k or 7.2k SATA mechanical drives, or SSD SAS/SATA. The backplane will accept any of the disks I’ve listed.

Let me know if you need anything else






16 Posts

May 4th, 2023 03:00

Hey Rick

Thanks for the question.

A couple of points to start with, a virtual drive is made up of multiple disks that form a raid level. If you create a virtual disk, let’s stick with the raid 1 example, then all the drives within that raid level must be the same technology. In other words, you cannot mix SSD SATA drives with SSD SAS drives. All drives need to be same technology.

However, you can MIX different technology of drives within a backplane.  So, for instance you could keep your existing raid 1 that contains the two SSD SATA 1.9 TB drives and add different technology of drives to the remaining slots. These drives could be SSD SAS, or they could be SAS or SATA mechanical drives.

If you go for the less expensive mechanical drives (SAS or SATA) they will not have any impact on the performance of the raid 1 as the new drives will be in another raid level (virtual drive) that is independent of the existing raid 1.

In the example below your existing raid 1 is listed and 5 x SAS mechanical drives make up a raid 5, the number of disks in the raid 5 is dependent on how large you want it to be. You need a minimum of 3 drives but with your backplane you could have up to 6 in it. You could also choose a different raid level based on your needs, but that would be dependent on how many disks you purchase.




Kind regards



8 Posts

May 4th, 2023 10:00

Wow!  Thanks Emmet for that write-up!  

Now you're making me wonder a little.

So, if I'm following correctly, I could leave the existing RAID-1 array alone (comprised of the two 1.92Tb SSD SATA drives) and buy 6 other drives using other technologies (e.g. SAS, mechanical, etc) and plug them into the front of the R350 server in the empty slots and go from there?  I didn't know that.. IF I'm wrong please let me know!  Thank you!


8 Posts

May 4th, 2023 11:00

One additional question for you.. The connectors that are used in the front panel drive inserts (whatever they're called), are they capable of talking to SAS & SATA drives in a single connector and as long as we buy the Dell drives they just ought to work without fiddling around?  I just wanted to check that I won't have any issues with buying SAS drives but the front panel slide-ins are assuming SATA or something.

This is my assumption that the connectors will handle either but wanted to check.. Much appreciated!!



8 Posts

May 9th, 2023 12:00

Wow Emmet!  You're amazing!  Thank you for the EXTREMELY thorough write-up!  I very very very much appreciate your efforts!  

Now if I could only get our sales guy to reply to me to actually buy the items I'm looking for...  I'm tempted to just order off the website after selecting our server and letting the website pick what can be used with it.. 

No Events found!