I think I actually have very bad fragmentation values, which unfortunately involve performances drop by an order of magnitude of 3x/4x. A defrag is actually running, but it's really really slow, to the point that I will need to constantly defrag the partition, which is not optimal. There are approximatively 500Go written sequentially every day, and almost 10/12T random writes every week due to backup files rotations. The partition has been formated with default options, over LVM (one VG/one LV). Here are somes questions : - is there mkfs.xfs or mounting options that could reduce the fragmentation over the time ? - the backup software writes use blocks size of ~4MB, as the previous question, any options to optimize differents layers (LVM & XFS) ? The underlaying FS could handle 1MB block size, should I set this value for XFS too ? do I need to play with "su" and "sw" as stated in the FAQ ? I admit that there are so many options that I am a bit lost. Thanks, Cédric -- Some informations : VM running Debian Jessie, underlaying storage is software raid (ZFS). df -k Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/VG2-LV1 53685000192 40921853928 12763146264 77% /vrepo1 xfs_db -r /dev/VG2/LV1 -c frag actual 4222, ideal 137, fragmentation factor 96.76% xfs_info /dev/VG2/LV1 meta-data=/dev/mapper/VG2-LV1 isize=256 agcount=50, agsize=268435455 blks = sectsz=512 attr=2, projid32bit=1 = crc=0 finobt=0 data = bsize=4096 blocks=13421771776, imaxpct=5 = sunit=0 swidth=0 blks naming =version 2 bsize=4096 ascii-ci=0 ftype=0 log =internal bsize=4096 blocks=521728, version=2 = sectsz=512 sunit=0 blks, lazy-count=1 realtime =none extsz=4096 blocks=0, rtextents=0 ls -lh total 26T -rw-rw-rw- 1 root root 20M Oct 13 23:45 SG DAILY BACKUP.vbm -rw-r--r-- 1 root root 550G Sep 20 09:08 SG DAILY BACKUP2015-09-04T200116.vrb -rw-r--r-- 1 root root 363G Oct 12 00:25 SG DAILY BACKUP2015-09-07T200129.vrb -rw-r--r-- 1 root root 156G Sep 12 22:40 SG DAILY BACKUP2015-09-08T200100.vrb -rw-r--r-- 1 root root 777G Oct 12 00:20 SG DAILY BACKUP2015-09-09T200100.vrb -rw-r--r-- 1 root root 472G Sep 19 09:11 SG DAILY BACKUP2015-09-10T200113.vrb -rw-r--r-- 1 root root 617G Sep 19 17:15 SG DAILY BACKUP2015-09-11T200105.vrb -rw-r--r-- 1 root root 484G Sep 20 01:14 SG DAILY BACKUP2015-09-14T200056.vrb -rw-r--r-- 1 root root 454G Sep 20 15:45 SG DAILY BACKUP2015-09-15T200119.vrb -rw-r--r-- 1 root root 374G Sep 20 15:48 SG DAILY BACKUP2015-09-16T200101.vrb -rw-r--r-- 1 root root 465G Sep 26 22:50 SG DAILY BACKUP2015-09-17T200105.vrb -rw-r--r-- 1 root root 626G Sep 27 08:43 SG DAILY BACKUP2015-09-18T200110.vrb -rw-r--r-- 1 root root 533G Sep 27 17:25 SG DAILY BACKUP2015-09-21T200101.vrb -rw-r--r-- 1 root root 459G Sep 28 02:36 SG DAILY BACKUP2015-09-22T200059.vrb -rw-r--r-- 1 root root 460G Sep 28 11:32 SG DAILY BACKUP2015-09-23T200111.vrb -rw-r--r-- 1 root root 516G Oct 12 00:27 SG DAILY BACKUP2015-09-24T200058.vrb -rw-r--r-- 1 root root 593G Oct 3 20:05 SG DAILY BACKUP2015-09-25T200104.vrb -rw-r--r-- 1 root root 482G Oct 12 00:20 SG DAILY BACKUP2015-09-28T200108.vrb -rw-r--r-- 1 root root 466G Oct 12 00:26 SG DAILY BACKUP2015-09-29T200115.vrb -rw-r--r-- 1 root root 481G Oct 4 23:41 SG DAILY BACKUP2015-09-30T200109.vrb -rw-r--r-- 1 root root 548G Oct 12 00:26 SG DAILY BACKUP2015-10-01T200115.vrb -rw-r--r-- 1 root root 703G Oct 11 07:59 SG DAILY BACKUP2015-10-02T200055.vrb -rw-r--r-- 1 root root 409G Oct 11 04:05 SG DAILY BACKUP2015-10-05T200106.vrb -rw-r--r-- 1 root root 384G Oct 11 10:14 SG DAILY BACKUP2015-10-06T200059.vrb -rw-r--r-- 1 root root 335G Oct 11 19:49 SG DAILY BACKUP2015-10-07T104621.vrb -rw-r--r-- 1 root root 552G Oct 12 00:27 SG DAILY BACKUP2015-10-07T200123.vrb -rw-r--r-- 1 root root 90G Oct 12 00:27 SG DAILY BACKUP2015-10-08T200113.vrb -rw-r--r-- 1 root root 13T Oct 12 00:27 SG DAILY BACKUP2015-10-09T200112.vbk -rw-r--r-- 1 root root 620G Oct 13 20:01 SG DAILY BACKUP2015-10-12T200108.vib -rw-r--r-- 1 root root 424G Oct 13 23:46 SG DAILY BACKUP2015-10-13T200136.vib pvdisplay /dev/sdc --- Physical volume --- PV Name /dev/sdc VG Name VG2 PV Size 50.00 TiB / not usable 3.00 MiB Allocatable yes (but full) PE Size 4.00 MiB Total PE 13107199 Free PE 0 Allocated PE 13107199 PV UUID nkbLG0-fUNx-StT7-htil-UksF-GC7i-amDIA9 vgdisplay VG2 --- Volume group --- VG Name VG2 System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 12 VG Access read/write VG Status resizable MAX LV 0 Cur LV 1 Open LV 1 Max PV 0 Cur PV 1 Act PV 1 VG Size 50.00 TiB PE Size 4.00 MiB Total PE 13107199 Alloc PE / Size 13107199 / 50.00 TiB Free PE / Size 0 / 0 VG UUID sjZjgR-M58f-Shrg-jxKu-TwBq-qL3X-BMXYEn lvdisplay /dev/VG2/LV1 --- Logical volume --- LV Path /dev/VG2/LV1 LV Name LV1 VG Name VG2 LV UUID rElcn9-cmsH-K3P5-nKOB-GcV0-fDf9-gozdgT LV Write Access read/write LV Creation host, time SG-VREPO1.ixblue.corp, 2015-08-09 10:40:53 +0200 LV Status available # open 2 LV Size 50.00 TiB Current LE 13107199 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 254:0 _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs