On 10/29/14 4:37 AM, Spelic wrote: > On 28/10/2014 18:39, Eric Sandeen wrote: >> Not formally planned, there are bits and pieces out there (i.e. the inode >> mover) which are part of what it might take to achieve a shrinker. >> >> Another option, rather than fs shrinking, is to use the dm-thinp target, which >> would allow you to allocate a large-but-sparse block device, create a very >> large filesystem on that, and add or remove storage as needed. >> (At least I think you can remove it...!) >> >> -Eric > > Thanks for your reply Eric > > Interesting technique, but for enforcing a maximum size (smaller than > the very large allocated thin device) I would have to rely on quotas, > which probably decreases performance. "probably" > Then using thinp would mess up > all the disk layout, basically replacing the XFS allocator, which > most likely would decrease performances significantly. "most likely" > And then the > thinp code itself is a medium performance thing and I don't think it > can keep up with XFS performances, so that would presumably be a hard > bottleneck. "presumably" > All this would result in a performance almost certainly > lower than ext4. "almost certainly..." All possibilities, but possibly also worth testing to find out. ;) It's true that today the thinp allocator will impact XFS allocation patterns to some degree. Anyway, shrink has been on the radar for years, it's just never really been a priority. It might happen some day... -Eric > Thanks > S. > _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
