On Tue, Oct 13, 2009 at 2:41 PM, Derek Simkowiak <[email protected]> wrote:
> With the rise of 1.5TB and 2.0TB drives in the past couple of years, I > think a SAN (or NAS) for ~4TB might be overkill. > > If you have the empty drive bays, then for ~$1000 you could put in a few > disks and just use Linux's software RAID. Four 2.0TB SATA disks could give > you 4TB of RAID1 or RAID6. > > If you're only up to 150GB so far, consider an interim setup of just > adding a couple of drives. For less than $500 you could put in 2TB of RAID1 > (dual disk) storage space. By the time that fills up, petabyte Flash drives > will be available :) > If you're only using 4 drives, Raid 10 (linux has a raid level that operates this way natively, but reshaping was not-yet supported when I last checked.)(or raid 0 across multiple raid 1 block devices) would yield superior performance across every dimension except fault tolerance. That is the one advantage raid6 would have with that few devices, any 2 could fail and data would still be intact; while with the raid solution the right two drives failing could corrupt/destroy half the data. Raid6 makes more sense with large quantities of devices (at least 6 IMO) when latency isn't as much of an issue as bandwidth. In particular Databases and small file serving operations probably operate better off of raid10/1+0; while most operations on large files would benefit more from the raid 0 (across N-redundancy) devices performance of raid 5/6 for the typical case of fault free operations.
