9/4/2023 0 Comments Sas drivesThe MegaRAID card Josh sent is PCIe Gen 3.1 and supports x8 lanes of PCIe bandwidth. But it is a compelling storage setup that was never possible until the Compute Module 4 came along. My Intel i3 desktop running by itself with no RAID card or storage attached idles at 25W but usually hovers around 40W-twice the power consumption, without a storage card installed.Ī Pi-based RAID solution isn't going to take over Amazon's data centers, though. If you don't need to pump through gigabytes per second, the Pi and MegaRAID together are more energy efficient than running software RAID on a faster CPU. Having a fast dedicated RAID chip and an extra 4 GB of DDR4 cache for storage gives the Pi reliable, fast disk IO. Second: using hardware RAID takes the IO burden of the Pi's already slow processor. The burden of having to go over to my other "desktop computer" desk to test means I am less likely to set things up on a whim to try out some new idea. When I do the same thing with my desktop, I quickly run out of space. In a tiny corner of my desk, I can put 8 drives, an enterprise RAID controller, my Pi, and some other gear for testing. Well, first of all, it's fun, I enjoy the challenge, and I get to learn a lot since failure teaches me a lot more than easy success.īut with this card, there are two other good reasons:įirst: it's great for a little storage lab. I even have a 10th-gen Intel desktop in my office, so, why not use that? People are always asking why I test all these cards-in this case, a storage card that costs $600 used-on low-powered Raspberry Pis. We'll get more into performance later, but first, I have to address the elephant in the room. That's a 20% performance increase, AND it leaves the Pi's CPU free to do other things. Using hardware RAID allowed me to get over 400 MB/sec. Parity calculations may make that maximum speed even lower! The fastest disk speed I could get with software mdadm-based RAID was about 325 MB/sec, and that was with RAID 10. (See this excellent post about /u/rigg77's ZFS experiment). If you can spend a couple thousand bucks on a fast PC with lots of RAM, software RAID solutions like ZFS or BTRFS offer a lot of great features, and are pretty reliable.īut on a system like my Raspberry Pi, software-based RAID takes up much of the Pi's CPU and RAM, and doesn't perform as well. And the best thing about a modern storage controller like the 9460-16i is that you can connect to all three through one single HBA (Host-Bus Adapter). I go into a lot more detail on RAID itself in my Raspberry Pi SATA RAID NAS video, so check that out to learn more.Īll three of these describe interfaces used for storage devices.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |