Courtesy: Patrick Yuen Photography & Imaging
FreeNAS – File-based
Anyone thinking of building something like this, I can’t urge you enough to use software RAID in Linux. It’s really not any more difficult to set up and you might have to follow a howto to replace a failed drive but everyone I’ve spoken with (3 other guys) that has had a hardware array has had problems rebuilding the array after a failure that resulted in data loss. We’re all using Linux software RAID now (8TB array, two 6TB arrays, and a 4TB array). We’ve all had to replace at least one drive (I’ve swapped four over time).
That last bit is a point about hard drives that I can’t underscore enough, and also re-enforces using software RAID. Hard drives are junk now, even with good cooling (sub 30 C) expect to replace a drive every couple of years at least. Be proactive and use SMART. It’s easy to do but many hardware RAID controllers don’t give you access to the SMART data from the drives whereas with software RAID it’s always available. Use SMART for two purposes: check the drive temperature and see if the drive has started to fail. Make sure the drive temps are udner 35 C and if possible get them under 30 C. Ignore the “health status” of the drive, instead check the Reallocated Sector Count, Pending Sectors, and Offline Uncorrectable sectors. These counts should always be zero. When they start to increase it’s time to order that new drive because while the drive might have a year left in it, it probably has a month left in it at most. Be safe and just swap that drive out ASAP.
Also, if that controller fails, you’ll need to find another one of the same brand/type to use your array. With the Linux software solution you can slap those drives in any computer and boot a Linux CD and your data is accessible. And it works the same for everyone so you can get tons of info and help off the internet.
OpenFiler – Block-based (SAN) and File-based (NAS)