Hi! I am trying to create a sparse qemu qcow2 image on xfs. (Centos 6.3) Unfortunately this doesn't produce the expected results: Creating a 10G file results in 16GB of disk usage! Doing the same on ext4 produces a 10G sparse file with only 1.8M allocated... (See the block bitmaps below.) Is this related to dynamic speculative preallocation? http://serverfault.com/questions/406069/why-are-my-xfs-filesystems-suddenly-consuming-more-space-and-full-of-sparse-file Are there any recommended filesystem options that optimize xfs behavior for hosting (sparse) virtual disk images? Cheers, --leo -------------------- 8< -------------------- $ qemu-img create -f qcow2 -o 'preallocation=metadata' onxfs.img 10G Formatting 'onxfs.img', fmt=qcow2 size=10737418240 encryption=off cluster_size=65536 preallocation='metadata' $ du -hs onxfs.img 16G onxfs.img $ ls -ls onxfs.img 16253692 -rw-r--r-- 1 leo users 10739318784 Oct 2 14:22 onxfs.img # xfs_bmap -v onxfs.img onxfs.img: EXT: FILE-OFFSET BLOCK-RANGE AG AG-OFFSET TOTAL 0: [0..1023]: 168294344..168295367 3 (11007944..11008967) 1024 1: [1024..1049215]: hole 1048192 2: [1049216..1049727]: 168295368..168295879 3 (11008968..11009479) 512 3: [1049728..2097919]: hole 1048192 4: [2097920..3146495]: 165668600..166717175 3 (8382200..9430775) 1048576 5: [3146496..3146623]: hole 128 6: [3146624..5243775]: 163571448..165668599 3 (6285048..8382199) 2097152 7: [5243776..5244159]: hole 384 8: [5244160..9438463]: 159377144..163571447 3 (2090744..6285047) 4194304 9: [9438464..9439103]: hole 640 10: [9439104..17827711]: 52616968..61005575 1 (188168..8576775) 8388608 11: [17827712..17828991]: hole 1280 12: [17828992..20975231]: 105886128..109032367 2 (1028528..4174767) 3146240 # xfs_info /srv meta-data=/dev/mapper/vg_1-lv_srv isize=256 agcount=4, agsize=6553600 blks = sectsz=512 attr=2 data = bsize=4096 blocks=26214400, imaxpct=25 = sunit=0 swidth=0 blks naming =version 2 bsize=4096 ascii-ci=0 log =internal bsize=4096 blocks=12800, version=2 = sectsz=512 sunit=0 blks, lazy-count=1 realtime =none extsz=4096 blocks=0, rtextents=0 -------------------- 8< -------------------- $ qemu-img create -f qcow2 -o 'preallocation=metadata' onext4.img 10G Formatting 'onext4.img', fmt=qcow2 size=10737418240 encryption=off cluster_size=65536 preallocation='metadata' $ du -h onext4.img 1.8M onext4.img $ ls -ls onext4.img 1744 -rw-r--r-- 1 leo users 10739318784 Oct 2 14:25 onext4.img debugfs: stat /leo/onext4.img Inode: 1048578 Type: regular Mode: 0644 Flags: 0x80000 Generation: 3370152928 Version: 0x00000000:00000001 User: 501 Group: 100 Size: 10739318784 File ACL: 0 Directory ACL: 0 Links: 1 Blockcount: 3488 Fragment: Address: 0 Number: 0 Size: 0 ctime: 0x506add38:7909fe14 -- Tue Oct 2 14:25:28 2012 atime: 0x506add38:731c2ccc -- Tue Oct 2 14:25:28 2012 mtime: 0x506add38:7909fe14 -- Tue Oct 2 14:25:28 2012 crtime: 0x506add36:5320b76c -- Tue Oct 2 14:25:26 2012 Size of extra inode fields: 28 EXTENTS: (0): 33856, (16): 33872, (32-79): 33888-33935, (131152-131167): 34896-34911, (262240-262255): 36960-36975, (393328-393343): 39024-39039, (524416-524447): 41088-41119, (655520-655535): 43168-43183, (786608-786623): 45232-45247, (917696-917711): 47296-47311, (1048784-1048815) : 49360-49391, (1179888-1179903): 51440-51455, (1310976-1310991): 53504-53519, (1442064-1442079): 55568-55583, (1573152-1573183): 57632-5 7663, (1704256-1704271): 59712-59727, (1835344-1835359): 61776-61791, (1966432-1966447): 63840-63855, (2097520-2097551): 65904-65935, (22 28624-2228639): 67984-67999, (2359712-2359727): 70048-70063, (2490800-2490815): 72112-72127, (2621887-2621903): 74175-74191 -- e-mail ::: Leo.Bergolth (at) wu.ac.at fax ::: +43-1-31336-906050 location ::: IT-Services | Vienna University of Economics | Austria _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
