Btrfs: Add hot data tracking functionality
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From: Christian Stroetmann on 4 Aug 2010 14:50 Hola Everybody; On the 04.08.2010 19:40, Mingming Cao wrote: > On Thu, 2010-07-29 at 22:17 +1000, Dave Chinner wrote: > >> On Wed, Jul 28, 2010 at 03:00:48PM -0700, Mingming Cao wrote: >> >>> On Wed, 2010-07-28 at 01:38 +0200, Christian Stroetmann wrote: >>> >>>> At the 28.07.2010 00:00, Ben Chociej wrote: >>>> Wouldn't this feature be useful for other file systems as well, so that >>>> a more general and not an only Btrfs related solution is preferable? >>>> >>>> >>> Would certainly nice to add this feature to all filesystem, but right >>> now btrfs is the only fs which have multiple device support in itself. >>> >> Why does it even need multiple devices in the filesystem? All the >> filesystem needs to know is the relative speed of regions of it's >> block address space and to be provided allocation hints. everything >> else is just movement of data. You could keep the speed information >> in the device mapper table and add an interface for filesystems to >> query it, and then you've got infrastructure that all filesystems >> could hook into. >> >> The tracking features dont' appear to have anything btrfs specific >> in them, so t iseems wrong to implement it there just because you're >> only looking at btrfs' method of tracking multiple block devices >> and moving blocks.... >> >> > > I agree hot data tracking could be done at vfs layer. The current hot > data temperature calculation and indexing code is very self-contained, > and could be reuse to other fs or move up to vfs. We could define a > common interface to export to hot data tempreture out. The relocation > eventually has to be filesystem specific. btrfs does cow and knows where > is the data on/off SSD directly makes the relocation to and from very > straightforward. > > Thanks for your thumb up. But maybe other interested persons should also point their thumbs up at first before investing the effort of its implementation. I mentioned this feature, because it is a trend that got momentum in the area of (storage) virtualization and in this way in the fields of cloud computing and service computing as well. And: My both thumbs are already up. :D > Mingming > > Christian *<:o) O>-< -(D)>-< -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |