Re: 3T drives and RAID

On Sat, 30 Oct 2010 04:21:16 -0500
"Leslie Rhorer" [off-list ref] wrote:

	Md will automatically treat the oddball drive as if it had .5K
sectors, or does one need to tell ma (or the kernel) to do so?

You don't need to tell the kernel to do anything special - it should just
work.

md/raid5 (and raid6) do all writes as 4K blocks, 4K aligned (as the
stripe-cache is made of pages which are 4K).  So that fits perfectly with the
new drives.
If your filesystem issued a non-aligned read, then it could get down to the
device as a non-aligned read, but there is little performance penalty for
reads, only writes.
And XFS almost certainly does all IO in 4K multiples, so you should be fine.

In short: I can see no reason why it shouldn't work smoothly.

NeilBrown