Is hardware RAID worth it?

Is hardware RAID worth it?

• I am planning to build a home NAS server, and have managed to get my hands on the following- Core i3 3220 Ivy Bridge CPU 4 GB Kingston RAM Basic motherboard with dual gigabit LAN port 4x WD 3TB HDDS 64GB SSD (For OS) I plan on using linux as the OS, and RAID 5 disk array. Now my question is, should I buy a hardware RAID card or I should go with a software RAID in the linux distro ? Now I know a software RAID will take a chunk out of the resources, but then again this box is solely for storage and the quad core cpu and 4gig RAM won't be doing a lot. So if I go ahead with the current hardware and configure a software RAID, will I see reduced R/W speed compared to a hardware RAID setup ? I will mostly use it for storing HD movies and my huge flac library and I'll stream the content to my A/V receiver as well as my phone/laptop/tablet/desktop over gigabit LAN and Wi-Fi so any sort of lag will be unacceptable when streaming to multiple devices, and I suspect the RAID conf may become a bottleneck. Any suggestions ?

• Answer:

  Hmmm. 4 drives in raid 5, access over gige. Max transfer rate for a NAS is the slowest of the disk array or the network. Since the disk array in theory could provide 3 x the HD speed, looks like the network will be the limiting factor. Unless of course, the software raid slows every thing down by more than a factor of 3. Theory: Each 3TB WD stat drive should maintain 120MB/s. Connected to MB onboard sata, all the drives together can't max the 6.0gb/s (effectively 600MB/s) data rate, but they can come close. The Ivy bridge cpu can handle 2gb/s of raid 5 traffic, per core. The gige network maxes out at 1gb/s. Practice: http://lucatnt.com/2013/06/improve-software-raid-speed-on-linux/ protip: allocate some ram to buffer access to the raid via the software configuration. As both Tom and Daniel obliquely pointed out, your big issue here will be data integrity (or data corruption/loss) and not the amount of speed the the system provides. Both ZFS and advanced raid configurations attempt to address that issue. Do your homework on this if your data is important/unique to you. Hardware raid puts the extra CPU and ram on a separate card. The raid speed is faster with the dedicated hardware raid, but only on the server itself. For most cases, the gige network is the limiting factor, once the data leaves the server. Now, if you had a 10GBe network, things might change. At the moment however, 10GBe equipment (nics and switches) is too expensive to use for your home network. For the money you would spend on 10GBe switches and nics, you could get a managed gige switch with port bonding, some extra gige nics to support that and a new gaming rig as well. Bonded gige on the server would potentially allow multiple machines on your home network to see full gige speeds.