fragile Live Fedora ? Device-mapper Snapshot vs. Layered Fs solution (AUFS or Overlayfs)

Thu Jul 30 17:42:01 UTC 2015

users at lists.fedoraproject.org

I tend to run Live Linux on laptop for months without a shutdown (suspend /
resume only).
Ubuntu and Mint work in this mode well, until recently I want to give
Fedora a chance,
but it failed with IO Errors like this, when I did sudo yum install
something (or dnf install something),
this is always reproducible kernel panic whenever I run it on laptop
physical hardware, or in kvm,

with the current Fedora 22 Workstation image, I tested a few other spins as
well, failed the same
https://getfedora.org/en/workstation/download/
https://labs.fedoraproject.org/security/download/index.html

I wonder is this a well known issue ? on Fedora Bugzilla database ? If
under Live OS mode, the / doesn't support writing how can it be called Live
?

I researched a little more and figured out because Fedora Live mode runs on
top of dev-mapper snapshot driver while Ubuntu runs on Overlayfs that looks
more stable;
wonder are there some technical reasons why Fedora use dev-mapper snapshot
such immature driver ?

[  373.306048] device-mapper: snapshots: Invalidating snapshot: Unable to
allocate exception.
[  373.310022] Buffer I/O error on device dm-0, logical block 1609980
[  373.311236] Buffer I/O error on device dm-0, logical block 1609981
[  373.313031] Buffer I/O error on device dm-0, logical block 1609982
[  373.316023] Buffer I/O error on device dm-0, logical block 1609983
[  373.319126] Buffer I/O error on device dm-0, logical block 1609984
[  373.322136] EXT4-fs error (device dm-0): ext4_find_entry:1289: inode
#45749: comm kworker/u2:2: reading directory lblock 0
[  373.324414] Buffer I/O error on device dm-0, logical block 1609985
[  373.328306] Buffer I/O error on device dm-0, logical block 1609986
[  373.329445] Buffer I/O error on dev dm-0, logical block 0, lost sync
page write
[  373.331205] Buffer I/O error on device dm-0, logical block 1609987
[  373.332667] Buffer I/O error on device dm-0, logical block 1609988
[  373.337317] Buffer I/O error on device dm-0, logical block 1609989
[  373.338726] EXT4-fs error (device dm-0) in ext4_ext_truncate:4669: IO
failure
[  373.339935] EXT4-fs (dm-0): previous I/O error to superblock detected
[  373.341146] Buffer I/O error on dev dm-0, logical block 0, lost sync
page write
[  373.342554] EXT4-fs error (device dm-0) in ext4_ext_truncate:4669: IO
failure
[  373.343961] EXT4-fs (dm-0): previous I/O error to superblock detected
[  373.352119] Buffer I/O error on dev dm-0, logical block 0, lost sync
page write
[  373.359310] audit: *NO* daemon at audit_pid=789
[  373.360056] audit: auditd disappeared
[  373.858134] Aborting journal on device dm-0-8.
[  373.858877] Buffer I/O error on dev dm-0, logical block 12679, lost sync
page write
[  373.860548] JBD2: Error -5 detected when updating journal superblock for
dm-0-8.
[  373.862332] EXT4-fs (dm-0): previous I/O error to superblock detected
[  373.863432] Buffer I/O error on dev dm-0, logical block 0, lost sync
page write
[  373.865080] EXT4-fs error (device dm-0): ext4_journal_check_start:56:
Detected aborted journal
[  373.866572] EXT4-fs (dm-0): Remounting filesystem read-only
[  373.867539] EXT4-fs (dm-0): previous I/O error to superblock detected
[  373.869236] Buffer I/O error on dev dm-0, logical block 0, lost sync
page write
[  373.939115] EXT4-fs error (device dm-0): ext4_find_entry:1289: inode
#145895: comm gmain: reading directory lblock 0
[  373.939854] EXT4-fs (dm-0): previous I/O error to superblock detected
[  373.940415] Buffer I/O error on dev dm-0, logical block 0, lost sync
page write
[  374.132832] Kernel panic - not syncing: Attempted to kill init!
exitcode=0x0000000b
[  374.132832]
[  374.133007] CPU: 0 PID: 1 Comm: systemd Not tainted
4.0.4-301.fc22.x86_64 #1
[  374.133007] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.8.1-20150604_211837-tipua 04/01/2014
[  374.133007]  0000000000000000 00000000a3109a5c ffff880052487c68
ffffffff81782644
[  374.133007]  0000000000000000 ffffffff81a4c850 ffff880052487ce8
ffffffff817813b4
[  374.133007]  ffffffff00000010 ffff880052487cf8 ffff880052487c98
00000000a3109a5c
[  374.133007] Call Trace:
[  374.133007]  [<ffffffff81782644>] dump_stack+0x45/0x57
[  374.133007]  [<ffffffff817813b4>] panic+0xd0/0x203
[  374.133007]  [<ffffffff8109f69d>] do_exit+0xb3d/0xb40
[  374.133007]  [<ffffffff8109f737>] do_group_exit+0x47/0xb0
[  374.133007]  [<ffffffff810ab5dc>] get_signal+0x27c/0x610
[  374.133007]  [<ffffffff81013547>] do_signal+0x37/0x760
[  374.133007]  [<ffffffff81013cef>] do_notify_resume+0x7f/0xa0
[  374.133007]  [<ffffffff81789952>] retint_signal+0x48/0x86
[  374.133007] Kernel Offset: 0x0 from 0xffffffff81000000 (relocation
range: 0xffffffff80000000-0xffffffff9fffffff)
[  374.133007] drm_kms_helper: panic occurred, switching back to text
console
[  374.133007] ---[ end Kernel panic - not syncing: Attempted to kill init!
exitcode=0x0000000b
[  374.133007]

[liveuser at localhost ~]$ df -Th

Filesystem          Type      Size  Used Avail Use% Mounted on
devtmpfs            devtmpfs  662M     0  662M   0% /dev
tmpfs               tmpfs     682M   72K  682M   1% /dev/shm
tmpfs               tmpfs     682M  840K  681M   1% /run
tmpfs               tmpfs     682M     0  682M   0% /sys/fs/cgroup
/dev/vda1           iso9660   889M  889M     0 100% /run/initramfs/live
/dev/mapper/live-rw ext4      9.8G  2.7G  7.0G  28% /
tmpfs               tmpfs     682M   12K  682M   1% /tmp
vartmp              tmpfs     682M     0  682M   0% /var/tmp
varcacheyum         tmpfs     682M     0  682M   0% /var/cache/yum
tmpfs               tmpfs     137M  8.0K  137M   1% /run/user/1000
[liveuser at localhost ~]$ df -Th -x tmpfs
Filesystem          Type      Size  Used Avail Use% Mounted on
devtmpfs            devtmpfs  662M     0  662M   0% /dev
/dev/vda1           iso9660   889M  889M     0 100% /run/initramfs/live
/dev/mapper/live-rw ext4      9.8G  2.7G  7.0G  28% /
[liveuser at localhost ~]$
[liveuser at localhost ~]$ sudo losetup -a
/dev/loop0: [0019]:11530 (/run/initramfs/osmin.img)
/dev/loop1: [1792]:1 (/osmin)
/dev/loop2: [64513]:1998 (/run/initramfs/live/LiveOS/squashfs.img)
/dev/loop3: [1794]:2 (/LiveOS/ext3fs.img)
/dev/loop4: [0001]:11627 (/overlay (deleted))
[liveuser at localhost ~]$ sudo dmsetup table
live-base: 0 20971520 linear 7:3 0
live-osimg-min: 0 20971520 snapshot 7:3 7:1 P 8
live-rw: 0 20971520 snapshot 7:3 7:4 P 8
[liveuser at localhost ~]$

Thanks,
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