virt-alignment-scan(1) Virtualization Support virt-alignment-scan(1) (NAME) virt-alignment-scan - (SYNOPSIS) virt-alignment-scan [--options] -d domname virt-alignment-scan [--options] -a disk.img [-a disk.img ...] virt-alignment-scan [--options] (DESCRIPTION) ( 63 ). / (I/O) . virt-alignment-scan . . . NetApp : http://media.netapp.com/documents/tr-3747.pdf (OUTPUT) -a : $ virt-alignment-scan -a winxp.img /dev/sda1 32256 512 bad (alignment < 4K) $ virt-alignment-scan -a fedora16.img /dev/sda1 1048576 1024K ok /dev/sda2 2097152 2048K ok /dev/sda3 526385152 2048K ok libvirt -d -c : # virt-alignment-scan -d RHEL5 /dev/sda1 32256 512 bad (alignment < 4K) /dev/sda2 106928640 512 bad (alignment < 4K) $ virt-alignment-scan -c qemu:///system -d Win7TwoDisks /dev/sda1 1048576 1024K ok /dev/sda2 105906176 1024K ok /dev/sdb1 65536 64K ok virt-alignment-scan -a -d libvirt . # virt-alignment-scan F16x64:/dev/sda1 1048576 1024K ok F16x64:/dev/sda2 2097152 2048K ok F16x64:/dev/sda3 526385152 2048K ok . . : ( /dev/sda1 ). libvirt ( -a -d ) libvirt UUID ( --uuid) : "WinXP:/dev/sda1" . ( 512 "4K"). "ok" "bad" . + . . << (EXIT STATUS)>> . -q . (OPTIONS) --help . -a file --add file file . . --format=.. . -a URI --add URI . "ADDING REMOTE STORAGE" guestfish(1) . --blocksize=512 --blocksize=4096 --blocksize . . --blocksize . "guestfs_add_drive_opts" guestfs(3) . -c URI --connect URI libvirt URI . libvirt . (-a) libvirt . -d guest --domain guest libvirt. UUID . --format=raw|qcow2|.. --format -a . -a . --format -a . : virt-alignment-scan --format=raw -a disk.img raw ( ) disk.img . virt-alignment-scan --format=raw -a disk.img --format -a another.img raw ( ) disk.img another.img . (raw) . (CVE-2010-3851). -P nr_threads 1.22 libguestfs virt-alignment-scan (multithreaded) . virt-alignment-scan . -P virt-alignment-scan "nr_threads" . -P 0 -P 1 . -q --quiet . ( << (EXIT STATUS)>> ). --uuid UUID . . libvirt ( -a -d ). -v --verbose . -V --version . -x API libguestfs. (RECOMMENDED ALIGNMENT) . . / / (CHS) BIOS . (track) . <<>> . : o . o (NAS). o . NetApp . o << (1 MB PARTITION ALIGNMENT)>> . / . : sect#63 | guest | | filesystem block | | host block | host block | | | | ( / ). ( /). / (LINUX HOST BLOCK AND I/O SIZE) / . : $ cat /sys/block/sda/queue/hw_sector_size 512 $ cat /sys/block/sda/queue/physical_block_size 512 $ cat /sys/block/sda/queue/logical_block_size 512 $ cat /sys/block/sda/queue/minimum_io_size 512 $ cat /sys/block/sda/queue/optimal_io_size 0 : $ cat /sys/block/sda/queue/hw_sector_size 4096 $ cat /sys/block/sda/queue/physical_block_size 4096 $ cat /sys/block/sda/queue/logical_block_size 4096 $ cat /sys/block/sda/queue/minimum_io_size 4096 $ cat /sys/block/sda/queue/optimal_io_size 0 NetApp LUN: $ cat /sys/block/sdc/queue/logical_block_size 512 $ cat /sys/block/sdc/queue/physical_block_size 512 $ cat /sys/block/sdc/queue/minimum_io_size 4096 $ cat /sys/block/sdc/queue/optimal_io_size 65536 NetApp ( ) / / . : http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Storage_Administration_Guide/newstorage-iolimits.html [ Matt Booth 4K. Mike Snitzer NetApp .] (1 MB PARTITION ALIGNMENT) Windows 2008 Server . ( ) . (4K, 64K) . (SETTING ALIGNMENT) virt-resize(1) . . . . (templates) . NetApp : http://media.netapp.com/documents/tr-3747.pdf Red Hat Enterprise Linux <= 5 Kickstart %pre parted(8) . Kickstart "part" . NetApp . (EXIT STATUS) : o 0 >= 64K o 1 o 2 < 64K o 3 < 4K (SEE ALSO) guestfs(3), guestfish(1), virt-filesystems(1), virt-rescue(1), virt-resize(1), http://libguestfs.org. (AUTHOR) Richard W.M. Jones http://people.redhat.com/~rjones (COPYRIGHT) Copyright (C) 2011 Red Hat Inc. (LICENSE) (GNU General Public License) ( ) / . . . Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA . (BUGS) libguestfs : https://bugzilla.redhat.com/buglist.cgi?component=libguestfs&product=Virtualization+Tools libguestfs : https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&product=Virtualization+Tools : o libguestfs. o libguestfs ( ). o . o libguestfs-test-tool(1) . guestfs-tools-1.56.0 2026-07-11 virt-alignment-scan(1)