Discussion:
[Bacula-users] Bacula Restore keeps crashing with "Block checksum mismatch"
Sven Hendriks
18 years ago
Permalink
Hello,

I'm running Bacula 2.0.2 built from source on the following system:
XEN 3.0 with Gentoo, Kernel 2.6.16 as Dom0 running bacula-dir and bacula-sd. One deamon bacula-fd is also running here for test restores. File system is Ext3.
Debian, Kernel 2.6.16 as DomU running one file daemon for backup. The file system here is XFS.
The backups are done from the DomU file daemon and are stored via the storage daemon on a samba share with NTFS mounted with the cifs option in the Dom0.

Backups are running well, unfortunately the Restores do not. Everytime I try to restore a backup sooner or later I get an error message like

"Error: block.c:317 Volume data error at 0:2068512761!
Block checksum mismatch in block=65353 len=64512: calc=3deeeba7 blk=962bd82e"

and later

"Error: attribs.c:409 File size of restored file XXXXX not correct. Original YYYYY, restored ZZZZZ."

and Bacula stops.

I tried to restore from the samba share to the same samba share into another directory via the file daemon on Dom0 and from the samba share to a XEN DomU with XFS via the file daemon on DomU. In both cases I get the error messages above. The backups are running at night, so it is very unlikely that file sizes are changing during backup. I hope my descriptions are not too confusing :-)
I have no idea what causes this error and I'd be grateful for any hint that may help to solve my little problem.

Greetings,
Sven Hendriks




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Kern Sibbald
18 years ago
Permalink
It looks to me like Samba shares don't support more that 2GB.

Recommendations:
- Don't write to any share of any kind (not Samba, not NFS, ...)
- If you absolutely must write to a Samba share try limiting the Volume size
to 2GB -- that may resolve the problem.
...
Alan Brown
18 years ago
Permalink
Post by Kern Sibbald
It looks to me like Samba shares don't support more that 2GB.
Incorrect. My CIFS servers are happily providing 1000+Gb shares.

It's certainly suboptimal for Bacula to be reading or writing to remote
shares though. Far better to put a samba-fd directly on the host machines.
Ryan Novosielski
18 years ago
Permalink
Post by Alan Brown
Post by Kern Sibbald
It looks to me like Samba shares don't support more that 2GB.
Incorrect. My CIFS servers are happily providing 1000+Gb shares.
It's certainly suboptimal for Bacula to be reading or writing to remote
shares though. Far better to put a samba-fd directly on the host machines.
Samba can be built without large file support, if the OS that it is
built on does not support it or similar reasons. There can be a 2GB
limit either within Samba or within the OS of the machine running Samba.
HP-UX, for example, has to have its filesystems formatted the right way
and to have Samba built the right way.

- --
---- _ _ _ _ ___ _ _ _
|Y#| | | |\/| | \ |\ | | |Ryan Novosielski - Systems Programmer III
|$&| |__| | | |__/ | \| _| |***@umdnj.edu - 973/972.0922 (2-0922)
\__/ Univ. of Med. and Dent.|IST/AST - NJMS Medical Science Bldg - C630
Sven Hendriks
18 years ago
Permalink
Hello Kern,

thank you very much for this hint, but the volume size is already limited to 2GB.

Greetings
Sven Hendriks
...
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Kern Sibbald
18 years ago
Permalink
Post by Sven Hendriks
Hello Kern,
thank you very much for this hint, but the volume size is already limited to 2GB.
Well, I don't think it is working correctly, because your output indicates
that Bacula is attempting to read at an address greater than 2,000,000,000
when it gets the error.
...
Ryan Novosielski
18 years ago
Permalink
Post by Kern Sibbald
Post by Sven Hendriks
Hello Kern,
thank you very much for this hint, but the volume size is already limited to 2GB.
Well, I don't think it is working correctly, because your output indicates
that Bacula is attempting to read at an address greater than 2,000,000,000
when it gets the error.
Incidentally, though off-topic for this list, Samba is capable of more
than 2GB files if it has been properly built for it.
- --
---- _ _ _ _ ___ _ _ _
|Y#| | | |\/| | \ |\ | | |Ryan Novosielski - Systems Programmer III
|$&| |__| | | |__/ | \| _| |***@umdnj.edu - 973/972.0922 (2-0922)
\__/ Univ. of Med. and Dent.|IST/AST - NJMS Medical Science Bldg - C630
Sven Hendriks
18 years ago
Permalink
Hello,

my problem seems to be solved. It seems to have something to do with the block size. I set both the minimum and the maximum blocksize of the device to 64KB and the restore works:

Device {
Name = TestStorage
Media Type = File
Archive Device = /mnt/notfallserver/vollbackup
LabelMedia = yes;
Random Access = Yes;
AutomaticMount = no;
RemovableMedia = no;
AlwaysOpen = yes;
RequiresMount = no;
Minimum Block Size = 65536
Maximum Block Size = 65536
}

It works with 16KB fixed block size, too. Beforehand I did not set the block size.

Greetings,
Sven Hendriks
Post by Sven Hendriks
Hello,
XEN 3.0 with Gentoo, Kernel 2.6.16 as Dom0 running bacula-dir and
bacula-sd. One deamon bacula-fd is also running here for test restores.
File system is Ext3. Debian, Kernel 2.6.16 as DomU running one file daemon
for backup. The file system here is XFS. The backups are done from the DomU
file daemon and are stored via the storage daemon on a samba share with
NTFS mounted with the cifs option in the Dom0.
Backups are running well, unfortunately the Restores do not. Everytime I
try to restore a backup sooner or later I get an error message like
"Error: block.c:317 Volume data error at 0:2068512761!
Block checksum mismatch in block=65353 len=64512: calc=3deeeba7
blk=962bd82e"
and later
"Error: attribs.c:409 File size of restored file XXXXX not correct.
Original YYYYY, restored ZZZZZ."
and Bacula stops.
I tried to restore from the samba share to the same samba share into
another directory via the file daemon on Dom0 and from the samba share to a
XEN DomU with XFS via the file daemon on DomU. In both cases I get the
error messages above. The backups are running at night, so it is very
unlikely that file sizes are changing during backup. I hope my descriptions
are not too confusing :-) I have no idea what causes this error and I'd be
grateful for any hint that may help to solve my little problem.
Greetings,
Sven Hendriks
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