Ceph » Linux kernel client

I was able to reproduce Fyodor's problem on rbd (latest kernel) and ext2:

root@uml:~# mke2fs /dev/rbd0
mke2fs 1.41.12 (17-May-2010)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
6406144 inodes, 25600000 blocks
1280000 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
782 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks: 
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
        4096000, 7962624, 11239424, 20480000, 23887872

Writing inode tables: done                            
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 39 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.
root@uml:~# mount /dev/rbd0 mnt
cd mnt
root@uml:~# cd mnt
root@uml:~/mnt# iozone -a -n4g -g20g
        Iozone: Performance Test of File I/O
                Version $Revision: 3.308 $
                Compiled for 64 bit mode.
                Build: linux 

        Contributors:William Norcott, Don Capps, Isom Crawford, Kirby Collins
                     Al Slater, Scott Rhine, Mike Wisner, Ken Goss
                     Steve Landherr, Brad Smith, Mark Kelly, Dr. Alain CYR,
                     Randy Dunlap, Mark Montague, Dan Million, Gavin Brebner,
                     Jean-Marc Zucconi, Jeff Blomberg, Benny Halevy,
                     Erik Habbinga, Kris Strecker, Walter Wong, Joshua Root.

        Run began: Thu May 12 16:20:59 2011

        Auto Mode
        Using minimum file size of 4194304 kilobytes.
        Using maximum file size of 20971520 kilobytes.
        Command line used: iozone -a -n4g -g20g
        Output is in Kbytes/sec
        Time Resolution = 0.000001 seconds.
        Processor cache size set to 1024 Kbytes.
        Processor cache line size set to 32 bytes.
        File stride size set to 17 * record size.
                                                            random  random    bkwd   record   stride                                   
              KB  reclen   write rewrite    read    reread    read   write    read  rewrite     read   fwrite frewrite   fread  freread
         4194304      64    3570    3040    12640    13725

Error in file: Found ?aaaaaaaaaaaaaaaa? Expecting ?3838383838383838? addr 40a00000
Error in file: Position 2813329408 
Record # 42928 Record size 64 kb 
where 40a00000 loop 0

Not sure yet if this is an osd or rbd problem.