On May 1, 2012, at 9:20 AM, Thomas Lunde wrote: > Ryan - > > From someone who has been bitten before: Beware RAID-5 rebuilding times! > > With N drives in R5, you can lose 1. If you lose a second during the rebuild, it's time to take the whole thing down and restore from backup. Since rebuild time is proportional to the size of the array and because hard drives are getting lots bigger without getting much faster, that rebuild time could be a lot longer than you expect. Yeah, I know but I'd rather have the capacity with the tolerance than not at all. > I've sworn off of RAID-5. > > RAID-10 or RAID-6 or just pairs of RAID-1 with LVM on top of it are all safer than 5. > > (Hmm - can anyone take a swing at characterizing the performance of RAID-10 vs. RAID-1 with LVM on top of it?) > > You mention adding 2, then 2 more. That gets my count to 6 drives. You said you have 4 bays. I would NOT run RAID over USB. (Yes, you can and I've done it to play with. Under load, I got enough random disconnects and errors that I wouldn't put it into production. ) That's the same 2, sorry. > Do you have enough SATA ports, physical space and cooling capacity to handle 6 drives? > > You mentioned that speed is not a concern. If you don't need the space now that 6 drives would provide, you might consider only using 4 and then doing this dance again with 4 TB drives in future. See above. > Andrew may have been driving at putting your boot device on another, smaller volume. I have a server that is stuffed with 2 TB drives, but the OS lives on a very small USB thumb drive. It barely touches it after the initial boot and lets me use the server's bays for "real" disc space. I could possibly see this... I'd probably look at one of those micro USB drives; but I'd have to get a few of them. I don't like the lifespan of Flash. > Just some thoughts. > Thomas > Thanks, Thomas. I'll look into the costs.