I have an older Dell R710 for my personal home server with a pair of PERC6i raid cards in it. I have a drive array attached to one of them where the data lives on different RAIDs, the other PERC6 is attached to the R710's 8 drive bays.

I'm abandoning tape as a backup and moving to disc drives, which I will rotate off site. I am trying to figure out which would be the faster device. In both cases, a spinning drive, not a SSD is preferred as I've read many SSDs can lose their data when shelved, and powered off. I understand that is less likely with a regular disc drive. So, assuming similar drive specs, which would be faster for throughput:

a) A PERC6i connected drive running raid 0 (single drive) or b) Add a PCIe USB3.0 card and use USB 3.0 (or USB C) external drives.

Cost-wise they are similar. The latter USB 3.0 option is probably more convenient, readily portable, and has broad compatibility with a restore or access. But, an external USB 30 non SSD drive may be hard to get before long.

If the hotswappable drive bay is faster by much, I can get some drive caddys and use that as my backup device..

I'm fuzzy on what should be faster. I gather the PERC6 is a 3 Gbps device while USB3.0 can do 5 Gbps. The R710 manual says that PCIe gen 2 is supported, there are 2 PCIe x8 slots and I think that limit is 500MBps so I assume the PCI won't be a bottleneck to USB3.

  • I will add that as I look at available USB 3.0 external drives, the disc based units are already looking to be going away. Anything with USB C was SSD. Probably before long they will all be SSD.
    – shorton
    Apr 12, 2019 at 15:33

1 Answer 1


I would use USB if you need to get your data offsite, not for speed reason, but to be practical. Hot swapping the USB disk is easier in the OS to manage, versus the hotswap of an internal HDD, where if you insert a new one you have and to create the array and attribute a letter to it. You might have to script that part, so the USB option win, even if it can be slower.

Not to forget that if you restore, you would need a Dell hardware to read your backup, versus the USB disk that you can read on any servers.

  • FWIW, I found that if I unplug a RAID 0 disc from the PERC, and plug it into a simple USB dock on my desktop, the files are there and readable just like any other drive. I only do periodic backups every few months, enough to preserve photos removed form memory cards, etc. My "live" data gets backed up more regularly at the desktop. Once a disc is set as RAID0 i would expect it to remember it when reinserted once rotated. So I get your points, but I still want to know what should be faster.
    – shorton
    Apr 12, 2019 at 15:31

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