Is there a way, with Linux md (or maybe lvm) to create a single mass storage device from many physical drives, but with the property that if one drive fails, all data isn't lost, AND no redundancy? I.e., similar to RAID-0, but if one drive dies, all data (but that on the failed drive) is still readily available? Motivation: I currently have a four-disc RAID5 device for media storage. The typical usage pattern is few writes, many reads, lots of idle time. I got to thinking, with proper backups, RAID really only buys me availability or performance, neither of which are a priority. Modern single-disc speed is more than enough, and high-availability isn't a requirement for a home media server. So I have four discs constantly running, using a fair amount of power. And I need more space, so the power consumption only goes up. I experimented a while with letting the drives spindown (hdparm -S), but (1) it was obnoxious waiting for all four discs to spinup when I wanted the data (they spunup in series---good for the power supply, bad for latency); and (2) I felt that having all four discs spinup was too much wear and tear on the drives, when, in principle, only one drive needed to spin up. I got to thinking, I could just have a bunch of individual drives, let them all spindown, and when data is needed, only spinup the one drive that has the data I want. Less wear and tear overall, lower overall power consumption, and lower access latency (compared to the whole RAID spinup). I know I could do this manually with symlinks. E.g., have a directory like /bigstore that contains symlinks into /mnt/drive1, /mnt/drive2, /mnt/drive3, etc. And then if one drive dies, the whole store isn't trashed. This seems fairly simple, so I wonder if there's not some automatic way to do it. Hence, this email. :) Thanks for any thoughts or suggestions! Matt -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
