one of my KVM VMs keeps data on BTRFS on top of encrypted LUKS drive. that drive is a block device passed from virtualization server to VM… a block device which is mdadm software RAID10. below – steps taken to resize it.
\n<\/p>\n
how is the block device passed to the VM? by using driver’s type=’raw’, here’s the relevant part of \/etc\/libvirt\/qemu\/myvm.xml:<\/p>\n
\r\n <devices>\r\n <emulator>\/usr\/bin\/qemu-system-x86_64<\/emulator>\r\n <disk type='file' device='disk'>\r\n <driver name='qemu' type='qcow2'\/>\r\n <source file='\/mnt\/kvm\/myvm\/myvm-disk1.qcow2'\/>\r\n <target dev='vda' bus='virtio'\/>\r\n <address type='pci' domain='0x0000' bus='0x03' slot='0x00' function='0x0'\/>\r\n <\/disk>\r\n <disk type='block' device='disk'>\r\n <driver name='qemu' type='raw'\/>\r\n <source dev='\/dev\/md127'\/>\r\n <target dev='vdb' bus='virtio'\/>\r\n <address type='pci' domain='0x0000' bus='0x05' slot='0x00' function='0x0'\/>\r\n <\/disk>\r\n ...\r\n<\/pre>\nthat’s how block devices look like on the virtualization host:<\/p>\n
\r\nroot@virtserver ~ # lsblk\r\nNAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT\r\nsda 8:0 0 5.5T 0 disk\r\n\u251c\u2500sda1 8:1 0 1G 0 part\r\n\u2502 \u2514\u2500md0 9:0 0 1022M 0 raid1 \/boot\r\n\u251c\u2500sda2 8:2 0 10G 0 part\r\n\u2502 \u2514\u2500md1 9:1 0 10G 0 raid1 \/\r\n\u251c\u2500sda3 8:3 0 1M 0 part\r\n\u2514\u2500sda4 8:4 0 2.1T 0 part\r\n \u2514\u2500md127 9:127 0 4.2T 0 raid10\r\nsdb 8:16 0 5.5T 0 disk\r\n\u251c\u2500sdb1 8:17 0 1G 0 part\r\n\u2502 \u2514\u2500md0 9:0 0 1022M 0 raid1 \/boot\r\n\u251c\u2500sdb2 8:18 0 10G 0 part\r\n\u2502 \u2514\u2500md1 9:1 0 10G 0 raid1 \/\r\n\u251c\u2500sdb3 8:19 0 1M 0 part\r\n\u2514\u2500sdb4 8:20 0 2.1T 0 part\r\n \u2514\u2500md127 9:127 0 4.2T 0 raid10\r\nsdc 8:32 0 5.5T 0 disk\r\n\u2514\u2500sdc1 8:33 0 2.1T 0 part\r\n \u2514\u2500md127 9:127 0 4.2T 0 raid10\r\nsdd 8:48 0 5.5T 0 disk\r\n\u2514\u2500sdd1 8:49 0 2.1T 0 part\r\n \u2514\u2500md127 9:127 0 4.2T 0 raid10\r\n\r\nroot@virtserver ~ # parted \/dev\/sda print\r\nModel: ATA HGST HUS726060AL (scsi)\r\nDisk \/dev\/sda: 6001GB\r\nSector size (logical\/physical): 512B\/4096B\r\nPartition Table: gpt\r\nDisk Flags: pmbr_boot\r\n\r\nNumber Start End Size File system Name Flags\r\n 3 1049kB 2097kB 1049kB bios_grub\r\n 1 2097kB 1076MB 1074MB raid\r\n 2 1076MB 11.8GB 10.7GB raid\r\n 4 11.8GB 2299GB 2287GB backup\r\n\r\nroot@virtserver ~ # parted \/dev\/sdb print\r\nModel: ATA HGST HUS726060AL (scsi)\r\nDisk \/dev\/sdb: 6001GB\r\nSector size (logical\/physical): 512B\/4096B\r\nPartition Table: gpt\r\nDisk Flags: pmbr_boot\r\n\r\nNumber Start End Size File system Name Flags\r\n 3 1049kB 2097kB 1049kB bios_grub\r\n 1 2097kB 1076MB 1074MB raid\r\n 2 1076MB 11.8GB 10.7GB raid\r\n 4 11.8GB 2299GB 2287GB backup\r\n\r\nroot@virtserver ~ # parted \/dev\/sdc print\r\nModel: ATA HGST HUS726060AL (scsi)\r\nDisk \/dev\/sdc: 6001GB\r\nSector size (logical\/physical): 512B\/4096B\r\nPartition Table: gpt\r\nDisk Flags:\r\n\r\nNumber Start End Size File system Name Flags\r\n 1 1049kB 2287GB 2287GB backup\r\n\r\nroot@virtserver ~ # parted \/dev\/sdd print\r\nModel: ATA HGST HUS726060AL (scsi)\r\nDisk \/dev\/sdd: 6001GB\r\nSector size (logical\/physical): 512B\/4096B\r\nPartition Table: gpt\r\nDisk Flags:\r\n\r\nNumber Start End Size File system Name Flags\r\n 1 1049kB 2287GB 2287GB backup\r\n\r\nroot@virtserver ~ # cat \/proc\/mdstat\r\nPersonalities : [raid10] [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4]\r\nmd0 : active raid1 sdb1[1] sda1[0]\r\n 1046528 blocks super 1.2 [2\/2] [UU]\r\n\r\nmd1 : active raid1 sdb2[1] sda2[0]\r\n 10476544 blocks super 1.2 [2\/2] [UU]\r\n\r\nmd127 : active raid10 sda4[0] sdb4[1] sdd1[3] sdc1[2]\r\n 4466530304 blocks super 1.2 512K chunks 2 near-copies [4\/4] [UUUU]\r\n bitmap: 0\/17 pages [0KB], 131072KB chunk\r\n\r\nunused devices: <none>\r\n<\/pre>\nand that’s what the myvm sees:<\/p>\n
\r\nroot@myvm:~# lsblk\r\nNAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT\r\nvda 254:0 0 2.8G 0 disk\r\n\u2514\u2500vda1 254:1 0 2.8G 0 part \/\r\nvdb 254:16 0 4.2T 0 disk\r\n\u2514\u2500backup 253:0 0 4.2T 0 crypt \/mnt\/backup\r\n<\/pre>\nas you can see on each of the physical drives – sda-sdd – there’s over 3700GB of unallocated space. my aim is to use some of that space and increase size of \/dev\/mapper\/backup on myvm by enlarging \/dev\/md127 on the virtualization server.<\/p>\n
#1 – shut down the myvm virtual machine. possibly unnecessarily. <\/p>\n
#2 – resize the sda4, sdb4, sdc1, sdd1 by adding 2000GB of space to each:<\/p>\n
\r\nroot@virtserver ~ # parted \/dev\/sda\r\nGNU Parted 3.2\r\nUsing \/dev\/sda\r\nWelcome to GNU Parted! Type 'help' to view a list of commands.\r\n(parted) print\r\nModel: ATA HGST HUS726060AL (scsi)\r\nDisk \/dev\/sda: 6001GB\r\nSector size (logical\/physical): 512B\/4096B\r\nPartition Table: gpt\r\nDisk Flags: pmbr_boot\r\n\r\nNumber Start End Size File system Name Flags\r\n 3 1049kB 2097kB 1049kB bios_grub\r\n 1 2097kB 1076MB 1074MB raid\r\n 2 1076MB 11.8GB 10.7GB raid\r\n 4 11.8GB 2299GB 2287GB backup\r\n\r\n(parted) resizepart 4\r\nEnd? [2299GB]? 4299GB\r\n(parted)\r\nInformation: You may need to update \/etc\/fstab.\r\n\r\nroot@virtserver ~ # parted \/dev\/sdb\r\nGNU Parted 3.2\r\nUsing \/dev\/sdb\r\nWelcome to GNU Parted! Type 'help' to view a list of commands.\r\n(parted) print\r\nModel: ATA HGST HUS726060AL (scsi)\r\nDisk \/dev\/sdb: 6001GB\r\nSector size (logical\/physical): 512B\/4096B\r\nPartition Table: gpt\r\nDisk Flags: pmbr_boot\r\n\r\nNumber Start End Size File system Name Flags\r\n 3 1049kB 2097kB 1049kB bios_grub\r\n 1 2097kB 1076MB 1074MB raid\r\n 2 1076MB 11.8GB 10.7GB raid\r\n 4 11.8GB 2299GB 2287GB backup\r\n\r\n(parted) resizepart 4\r\nEnd? [2299GB]? 4299GB\r\n(parted)\r\nInformation: You may need to update \/etc\/fstab.\r\n\r\nroot@virtserver ~ # parted \/dev\/sdc\r\nGNU Parted 3.2\r\nUsing \/dev\/sdc\r\nWelcome to GNU Parted! Type 'help' to view a list of commands.\r\n(parted) print\r\nModel: ATA HGST HUS726060AL (scsi)\r\nDisk \/dev\/sdc: 6001GB\r\nSector size (logical\/physical): 512B\/4096B\r\nPartition Table: gpt\r\nDisk Flags:\r\n\r\nNumber Start End Size File system Name Flags\r\n 1 1049kB 2287GB 2287GB backup\r\n\r\n(parted) resizepart 1\r\nEnd? [2287GB]? 4287GB\r\n(parted)\r\nInformation: You may need to update \/etc\/fstab.\r\n\r\nroot@virtserver ~ # parted \/dev\/sdd\r\nGNU Parted 3.2\r\nUsing \/dev\/sdd\r\nWelcome to GNU Parted! Type 'help' to view a list of commands.\r\n(parted) print\r\nModel: ATA HGST HUS726060AL (scsi)\r\nDisk \/dev\/sdd: 6001GB\r\nSector size (logical\/physical): 512B\/4096B\r\nPartition Table: gpt\r\nDisk Flags:\r\n\r\nNumber Start End Size File system Name Flags\r\n 1 1049kB 2287GB 2287GB backup\r\n\r\n(parted) resizepart 1\r\nEnd? [2287GB]? 4287GB\r\n(parted)\r\nInformation: You may need to update \/etc\/fstab.\r\n<\/pre>\n#3 resize mdadm raid on top of sda4, sdb4, sdc1, sdd1:<\/p>\n
\r\nroot@virtserver ~ # dmesg\r\n[32503.362525] md127: detected capacity change from 4573727031296 to 8573726752768\r\n[32503.405402] md: resync of RAID array md127\r\nroot@virtserver ~ # cat \/proc\/mdstat\r\nPersonalities : [raid10] [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4]\r\nmd0 : active raid1 sdb1[1] sda1[0]\r\n 1046528 blocks super 1.2 [2\/2] [UU]\r\n\r\nmd1 : active raid1 sdb2[1] sda2[0]\r\n 10476544 blocks super 1.2 [2\/2] [UU]\r\n\r\nmd127 : active raid10 sda4[0] sdb4[1] sdd1[3] sdc1[2]\r\n 8372780032 blocks super 1.2 512K chunks 2 near-copies [4\/4] [UUUU]\r\n [==========>..........] resync = 54.5% (4567488064\/8372780032) finish=310.4min speed=204265K\/sec\r\n bitmap: 15\/32 pages [60KB], 131072KB chunk\r\n\r\nunused devices: <none>\r\n<\/pre>\n#4 start the myvm VM again<\/p>\n
\r\nroot@virtserver ~ # virsh start myvm\r\n<\/pre>\n#5 on myvm – open the luks container and resize it<\/p>\n
\r\nroot@myvm:~# cryptsetup luksOpen \/dev\/vdb backup\r\nEnter passphrase for \/dev\/vdb:\r\nroot@myvm:~# cryptsetup resize backup -v\r\nEnter passphrase for \/dev\/vdb:\r\nKey slot 0 unlocked.\r\nCommand successful.\r\nroot@myvm:~# mount \/dev\/mapper\/backup \/mnt\/backup\/\r\nroot@myvm:~# btrfs filesystem resize max \/mnt\/backup\/\r\nResize '\/mnt\/backup\/' of 'max'\r\nroot@myvm:~# dmesg\r\n[ 130.727318] BTRFS info (device dm-0): new size for \/dev\/mapper\/backup is 8573709975552\r\nroot@myvm:~# lsblk\r\nNAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT\r\nvda 254:0 0 2.8G 0 disk\r\n\u2514\u2500vda1 254:1 0 2.8G 0 part \/\r\nvdb 254:16 0 7.8T 0 disk\r\n\u2514\u2500backup 253:0 0 7.8T 0 crypt \/mnt\/backup\r\n<\/pre>\nthere we have it – more space available for the \/mnt\/backup!<\/p>\n","protected":false},"excerpt":{"rendered":"
one of my KVM VMs keeps data on BTRFS on top of encrypted LUKS drive. that drive is a block device passed from virtualization server to VM… a block device which is mdadm software RAID10. below – steps taken to resize it.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[17,51],"tags":[109,108],"class_list":["post-3101","post","type-post","status-publish","format-standard","hentry","category-tech","category-unimportant","tag-luks","tag-mdadm"],"_links":{"self":[{"href":"https:\/\/kudzia.eu\/b\/wp-json\/wp\/v2\/posts\/3101","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kudzia.eu\/b\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kudzia.eu\/b\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kudzia.eu\/b\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/kudzia.eu\/b\/wp-json\/wp\/v2\/comments?post=3101"}],"version-history":[{"count":2,"href":"https:\/\/kudzia.eu\/b\/wp-json\/wp\/v2\/posts\/3101\/revisions"}],"predecessor-version":[{"id":3103,"href":"https:\/\/kudzia.eu\/b\/wp-json\/wp\/v2\/posts\/3101\/revisions\/3103"}],"wp:attachment":[{"href":"https:\/\/kudzia.eu\/b\/wp-json\/wp\/v2\/media?parent=3101"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kudzia.eu\/b\/wp-json\/wp\/v2\/categories?post=3101"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kudzia.eu\/b\/wp-json\/wp\/v2\/tags?post=3101"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}