On Wed, Apr 23, 2014 at 11:21:54AM +0200, Ivan Pantovic wrote: > Hi Dave, > > >xfs_db> freesp > > from to extents blocks pct > > 1 1 52463 52463 0.00 > > 2 3 73270 181394 0.01 > > 4 7 134526 739592 0.03 > > 8 15 250469 2870193 0.12 > > 16 31 581572 13465403 0.58 > > 32 63 692386 32096932 1.37 > > 64 127 1234204 119157757 5.09
So these are the small free spaces that lead to problems. There's around 3 million small free space extents in the filesystems, totalling 7% of the free space. That's quite a lot, and it means that there is a good chance that small allocations will find these small free spaces rather than find a large extent and start from there. > > 128 255 91015 16690243 0.71 > > 256 511 18977 6703895 0.29 > > 512 1023 12821 8611576 0.37 > > 1024 2047 23209 33177541 1.42 > > 2048 4095 43282 101126831 4.32 > > 4096 8191 12726 55814285 2.39 > > 8192 16383 2138 22750157 0.97 > > 16384 32767 1033 21790120 0.93 > > 32768 65535 433 19852497 0.85 > > 65536 131071 254 23052185 0.99 > > 131072 262143 204 37833000 1.62 > > 262144 524287 229 89970969 3.85 > > 524288 1048575 164 124210580 5.31 > >1048576 2097151 130 173193687 7.40 > >2097152 4194303 22 61297862 2.62 > >4194304 8388607 16 97070435 4.15 > >8388608 16777215 26 320475332 13.70 > >16777216 33554431 6 133282461 5.70 > >33554432 67108863 12 616939026 26.37 > >134217728 268435328 1 207504563 8.87 There are some large free spaces still, so your filesystem is still in fairly good shape from that perspective. You can get a better idea of whether the fragmentation is isolated to specific AGs by using the freesp -a <agno> command to dump each individual freespace index. You can then use the xfs_bmap command to find files that are located in those fragmented AGs. The only way to fix freespace fragmentation right now is to remove the extents that are chopping up the freespace. Moving data around on a per-directory basis (e.g. cp the regular files to a temp directory, rename them back over the original) is one way of acheiving this, though you have to carefully control the destination AG and make sure it is an AG that is made up mostly of contiguous freespace to begin with.... But you only really need to do this if you are seeing ongoing problems. Often just freeing up space in the filesystem will fix the problem... Cheers, Dave. -- Dave Chinner da...@fromorbit.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
