NAS Upgrades
A coworker brought four terabyte Hitachi drives in to work recently to recycle. The raid array they were in was giving warnings about degraded performance. I connected them to a workstation with an external SATA dock and ran Crystal Disk Info to check their SMART status. Surprisingly, none of them indicated any issues, even after copying a few hundred gigabytes back and forth.
The case my NAS was in before was only a mini-atx tower with one internal 3.5" bay and two 3.5" floppy bays, one of which I used for the OS disk. I needed more physical space for disks.
I ended up getting a Rosewill R4000 4U rackmount case. It has space for up to eight internal 3.5" drives and two 120mm fans to keep all the 3.5" bays cool.
I have been considering setting up a RAID array for quite a while. I looked into using nForce raid (software raid provided by the nVidia northbridge on my hardware), and ultimately decided against it due to poor linux support and poor performance. I also considered buying an LSI RAID card or a Dell PERC 6i, which is simply a re-branded LSI. LSI brand cards are a bit out of my budget, and the PERC 6i is somewhat of a hack. Although this server is socket 775 based it wouldn't experience the main issues with using a PERC 6i since it's an nVidia northbridge instead of an Intel one, I still had my doubts about how well it would perform without the battery backup unit typical of PERC 6i setups. Without the battery, a PERC 6i runs about $50, and the 4xSATA cable runs about $20. The battery adds another $30-50, depending on whether you buy a used one or aftermarket replacement. Initially it seemed I was out of options, but then I looked at using ZFS to make a sort of software RAID (known as RAID-Z). You can even set up hot-spare drives to immediately replicate to in the event of a drive failure.
ZFS has another main feature in that it is incredibly simple to set up. Just tell it what drives you want to use for the pool, what drives you want to use as a spare, and where you want to mount it. The ZFS setup utilities will handle the rest. Above are the results of running 'zpool status' on my NAS. sdb, sdc, and sdd are regular drives in the zpool and sde is configured as a hot-spare.