Re: [linux-lvm] Can't create thin lv

[Zdenek Kabelac <zkabelac@redhat.com>]

Dne 26.7.2018 v 09:24 Marc MERLIN napsal(a):
> On Wed, Jul 25, 2018 at 05:41:54PM -0700, Marc MERLIN wrote:
>> Howdy,
>>
>> Kernel 4.17, trying thin LV for the first time, and I'm getting this:
>> gargamel:~# lvcreate -L 14.50TiB -Zn -T vgds2/thinpool2
>>    Using default stripesize 64.00 KiB.
>>    Thin pool volume with chunk size 8.00 MiB can address at most <1.98 PiB of data.
>>    /dev/mapper/vgds2-thinpool2_tmeta: open failed: No such file or directory
>>    Failed to activate new LV.
>>
>> any idea what I should try next?
> 
> Interestingly I got a different error, once:
> gargamel:~# lvcreate -L 14.50TiB -Zn -T vgds2/thinpool2
>    Using default stripesize 64.00 KiB.
>    Thin pool volume with chunk size 8.00 MiB can address at most <1.98 PiB of data.
>    /dev/vgds2/lvol0: not found: device not cleared
>    Aborting. Failed to wipe start of new LV.
> 
> gargamel:~# mkdir /dev/vgds2/
> gargamel:~# l /dev/mapper/
> total 0
> drwxr-xr-x  2 root root     200 Jul 25 17:27 ./
> drwxr-xr-x 20 root root    5280 Jul 26 00:15 ../
> crw-------  1 root root 10, 236 Jul 25 17:25 control
> lrwxrwxrwx  1 root root       7 Jul 23 08:57 cryptroot -> ../dm-0
> lrwxrwxrwx  1 root root       7 Jul 25 06:40 dshelf1 -> ../dm-1
> lrwxrwxrwx  1 root root       7 Jul 26 00:11 dshelf2 -> ../dm-2
> lrwxrwxrwx  1 root root       7 Jul 25 06:40 eswap1 -> ../dm-3
> lrwxrwxrwx  1 root root       7 Jul 25 06:40 raid0d1 -> ../dm-4
> lrwxrwxrwx  1 root root       7 Jul 25 06:40 raid0d2 -> ../dm-5
> lrwxrwxrwx  1 root root       7 Jul 25 06:40 varchange -> ../dm-6
> gargamel:~# vgchange -ay
>    0 logical volume(s) in volume group "vgds2" now active
> 
> gargamel:~# lvcreate -L 14.50TiB -Zn -T vgds2/thinpool2
>    Using default stripesize 64.00 KiB.
>    Thin pool volume with chunk size 8.00 MiB can address at most <1.98 PiB of data.
>    /dev/mapper/vgds2-thinpool2_tmeta: open failed: No such file or directory
>    Failed to activate new LV.
> 
> gargamel:~# psg lvm
> root      2378  0.0  0.0  31600   488 ?        Ss   Jul25   0:00 /sbin/lvmetad
> 
> gargamel:~# lvcreate --version
>    LVM version:     2.02.176(2) (2017-11-03)
>    Library version: 1.02.145 (2017-11-03)
>    Driver version:  4.39.0
>    Configuration:   ./configure --build=i686-linux-gnu --prefix=/usr --includedir=${prefix}/include --mandir=${prefix}/share/man --infodir=${prefix}/share/info --sysconfdir=/etc --localstatedir=/var --disable-silent-rules --libdir=${prefix}/lib/i386-linux-gnu --libexecdir=${prefix}/lib/i386-linux-gnu --runstatedir=/run --disable-maintainer-mode --disable-dependency-tracking --exec-prefix= --bindir=/bin --libdir=/lib/i386-linux-gnu --sbindir=/sbin --with-usrlibdir=/usr/lib/i386-linux-gnu --with-optimisation=-O2 --with-cache=internal --with-clvmd=corosync --with-cluster=internal --with-device-uid=0 --with-device-gid=6 --with-device-mode=0660 --with-default-pid-dir=/run --with-default-run-dir=/run/lvm --with-default-locking-dir=/run/lock/lvm --with-thin=internal --with-thin-check=/usr/sbin/thi
>   n_check --with-thin-dump=/usr/sbin/thin_dump --with-thin-repair=/usr/sbin/thin_repair --enable-applib --enable-blkid_wiping --enable-cmdlib --enable-cmirrord --enable-dmeventd --enable-dbus-service
>   --enable-lvmetad --enable-lvmlockd-dlm --enable-lvmlockd-sanlock --enable-lvmpolld --enable-notify-dbus --enable-pkgconfig --enable-readline --enable-udev_rules --enable-udev_sync
> 
> 
> strace shows:
> openat(AT_FDCWD, "/dev/vgds2/lvol0", O_RDWR|O_DIRECT|O_LARGEFILE|O_NOATIME) = 7
> openat(AT_FDCWD, "/proc/self/maps", O_RDONLY|O_LARGEFILE) = 7
> openat(AT_FDCWD, "/dev/urandom", O_RDONLY|O_LARGEFILE) = 8
> openat(AT_FDCWD, "/proc/self/maps", O_RDONLY|O_LARGEFILE) = 7
> stat64("/dev/mapper/dshelf2", {st_mode=S_IFBLK|0660, st_rdev=makedev(253, 2), ...}) = 0
> stat64("/dev/mapper/dshelf2", {st_mode=S_IFBLK|0660, st_rdev=makedev(253, 2), ...}) = 0
> openat(AT_FDCWD, "/sys/dev/block/253:7/bdi/read_ahead_kb", O_RDONLY|O_LARGEFILE) = 7
> openat(AT_FDCWD, "/sys/dev/block/253:7/bdi/read_ahead_kb", O_WRONLY|O_LARGEFILE) = 7
> stat64("/dev/mapper/control", {st_mode=S_IFCHR|0600, st_rdev=makedev(10, 236), ...}) = 0
> openat(AT_FDCWD, "/dev/mapper/control", O_RDWR|O_LARGEFILE) = 4
> stat64("/dev/vgds2/thinpool2", {st_mode=S_IFBLK|0660, st_rdev=makedev(253, 7), ...}) = 0
> lstat64("/dev/vgds2/thinpool2", {st_mode=S_IFLNK|0777, st_size=7, ...}) = 0
> lstat64("/dev/vgds2/lvol0", 0xffe9462c) = -1 ENOENT (No such file or directory)
> stat64("/dev/vgds2/thinpool2", {st_mode=S_IFBLK|0660, st_rdev=makedev(253, 7), ...}) = 0
> openat(AT_FDCWD, "/dev/vgds2/thinpool2", O_RDWR|O_DIRECT|O_LARGEFILE|O_NOATIME) = 7
> openat(AT_FDCWD, "/proc/self/maps", O_RDONLY|O_LARGEFILE) = 7
> openat(AT_FDCWD, "/dev/urandom", O_RDONLY|O_LARGEFILE) = 8
> openat(AT_FDCWD, "/dev/urandom", O_RDONLY|O_LARGEFILE) = 8
> stat64("/sys//dev/block/253:2/queue/minimum_io_size", {st_mode=S_IFREG|0444, st_size=4096, ...}) = 0
> openat(AT_FDCWD, "/sys//dev/block/253:2/queue/minimum_io_size", O_RDONLY|O_LARGEFILE) = 7
> stat64("/etc/lvm/backup", {st_mode=S_IFDIR|0700, st_size=10, ...}) = 0
> access("/etc/lvm/backup", R_OK|W_OK|X_OK) = 0
> openat(AT_FDCWD, "/etc/lvm/backup/.lvm_gargamel.svh.merlins.org_19532_130993407", O_WRONLY|O_CREAT|O_EXCL|O_APPEND|O_LARGEFILE, 0666) = 7
> rename("/etc/lvm/backup/.lvm_gargamel.svh.merlins.org_19532_130993407", "/etc/lvm/backup/vgds2.tmp") = 0
> rename("/etc/lvm/backup/vgds2.tmp", "/etc/lvm/backup/vgds2") = 0
> stat64("/etc/lvm/backup/vgds2.tmp", 0xffe96b7c) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD, "/etc/lvm/backup", O_RDONLY|O_LARGEFILE) = 7
> openat(AT_FDCWD, "/proc/self/maps", O_RDONLY|O_LARGEFILE) = 7
> stat64("/dev/mapper/dshelf2", {st_mode=S_IFBLK|0660, st_rdev=makedev(253, 2), ...}) = 0
> stat64("/dev/mapper/dshelf2", {st_mode=S_IFBLK|0660, st_rdev=makedev(253, 2), ...}) = 0
> stat64("/dev/mapper/dshelf2", {st_mode=S_IFBLK|0660, st_rdev=makedev(253, 2), ...}) = 0
> stat64("/dev/mapper/dshelf2", {st_mode=S_IFBLK|0660, st_rdev=makedev(253, 2), ...}) = 0
> openat(AT_FDCWD, "/sys/dev/block/253:7/bdi/read_ahead_kb", O_RDONLY|O_LARGEFILE) = 8
> openat(AT_FDCWD, "/sys/dev/block/253:7/bdi/read_ahead_kb", O_WRONLY|O_LARGEFILE) = 8
> openat(AT_FDCWD, "/sys/dev/block/253:8/bdi/read_ahead_kb", O_RDONLY|O_LARGEFILE) = 8
> openat(AT_FDCWD, "/sys/dev/block/253:8/bdi/read_ahead_kb", O_WRONLY|O_LARGEFILE) = 8
> openat(AT_FDCWD, "/dev/mapper/vgds2-thinpool2_tmeta", O_RDONLY|O_LARGEFILE) = -1 ENOENT (No such file or directory)
>    /dev/mapper/vgds2-thinpool2_tmeta: open failed: No such file or directory
>    Failed to activate new LV.
> 
> 
> gargamel:~# strace -etrace=file lvcreate -L 14.50TiB -Zn -T vgds2/thinpool2 2>&1 |grep thinpool2
> execve("/sbin/lvcreate", ["lvcreate", "-L", "14.50TiB", "-Zn", "-T", "vgds2/thinpool2"], [/* 33 vars */]) = 0
> stat64("/dev/vgds2/thinpool2", {st_mode=S_IFBLK|0660, st_rdev=makedev(253, 7), ...}) = 0
> lstat64("/dev/vgds2/thinpool2", {st_mode=S_IFLNK|0777, st_size=7, ...}) = 0
> stat64("/dev/vgds2/thinpool2", {st_mode=S_IFBLK|0660, st_rdev=makedev(253, 7), ...}) = 0
> openat(AT_FDCWD, "/dev/vgds2/thinpool2", O_RDWR|O_DIRECT|O_LARGEFILE|O_NOATIME) = 7
> openat(AT_FDCWD, "/dev/mapper/vgds2-thinpool2_tmeta", O_RDONLY|O_LARGEFILE) = -1 ENOENT (No such file or directory)
>    /dev/mapper/vgds2-thinpool2_tmeta: open failed: No such file or directory
> 



Hi

What are you trying to achieve with 'mkdir /dev/vgds2/' ?

You shall never ever touch  /dev  content - it's always under full control of 
udev - if you start to create there your own files and directories you will
break whole usability of the system.

It's always udev having full control over all the symlinks there.

If you do not want to use udev - you need to compiled lvm2 without udev 
support - in this case  lvm2 will fallback to creation of all devices itself.

However I can't image in which todays distribution you would want to use it..

Anyway - the best 'debugging' you will get with  'lvcreate -vvvv'
it will always tell you what is failing.

Regards

Zdenek