On Fri, Nov 07, 2008 at 03:19:13PM -0500, Theodore Tso wrote: > Let's be just a *little* bit fair here. Suppose we wanted to > implement thin-provisioned disks using devicemapper and LVM; consider > that LVM uses a default PE size of 4M for some very good reasons. > Asking filesystems to be a little smarter about allocation policies so > that we allocate in existing 4M chunks before going onto the next, and > asking the block layer to pool trim requests to 4M chunks is not > totally unreasonable. > > Array vendors use chunk sizes > than typical filesystem chunk sizes > for the same reason that LVM does. So to say that this is due to > purely a "broken firmware architecture" is a little unfair. I think we would have a full-throated discussion about whether the right thing to do was to put the tracking in the block layer or in LVM. Rather similar to what we're doing now, in fact. -- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step." -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
