xtrabackup prepare problem

Hello,

I’m running Debian 6.0.2,
mysqld Ver 5.5.17-55-log for Linux on x86_64 (Percona Server (GPL), Release 22.1)

I’m creating backup doing:
xtrabackup_55 --backup --datadir=/var/lib/mysql --target-dir=/home/la/backup/

the create phase runs few minutes (the dataset is about 5G), and exits cleanly.

but prepare phase quickly fails:
$xtrabackup_55 --prepare --target-dir=/home/la/backup/

xtrabackup_55 version 1.6.3 for Percona Server 5.5.9 Linux (x86_64) (revision id: undefined)
xtrabackup: cd to /home/la/backup/
xtrabackup: This target seems to be not prepared yet.
xtrabackup: No valid checkpoint found.
xtrabackup: Error: xtrabackup_init_temp_log() failed.

I’m doing exactly the same steps as documentation says.

Here is some last lines of strace output:

open("./xtrabackup_logfile", O_RDWR) = 3
fadvise64(3, 0, 0, POSIX_FADV_SEQUENTIAL) = 0
fadvise64(3, 0, 0, POSIX_FADV_DONTNEED) = 0
lseek(3, 0, SEEK_END) = 17416192
mmap(NULL, 2117632, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f09aa5e7000
pread(3, "\0\0\0\0\0\0\0\1?\376\200\0\0\0\0\0xtrabkup 111206 "…, 2048, 0) = 2048
write(2, "xtrabackup: No valid checkpoint "…, 39xtrabackup: No valid checkpoint found.
) = 39
close(3) = 0
munmap(0x7f09aa5e7000, 2117632) = 0
write(2, “xtrabackup: Error: xtrabackup_in”…, 54xtrabackup: Error: xtrabackup_init_temp_log() failed.
) = 54
exit_group(1) = ?

Looks like a bug at first glance.

Maybe I can gather some additional information about this bug? Can you advice where to look?

here is my.cnf:

user = mysql
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /var/lib/mysql
tmpdir = /tmp
language = /usr/share/mysql/english

skip-external-locking
bind-address = 127.0.0.1
myisam-recover = BACKUP
expire_logs_days = 10
max_binlog_size = 100M
back_log = 75

log_slow_queries=/var/log/mysql/slow_queries.log
long_query_time=0.2
log_error = /var/log/mysql/mysql-error.log

max_connections = 300
key_buffer = 16M
myisam_sort_buffer_size=16M
join_buffer_size = 8M

table_cache = 132656
thread_cache_size = 384
wait_timeout = 60
connect_timeout = 3
tmp_table_size = 128M
max_heap_table_size = 128M
max_allowed_packet = 64M
max_connect_errors = 10

query_cache_size = 128M
query_cache_type = 1
query_cache_min_res_unit=512
max_connect_errors = 10000
query_prealloc_size = 163840
query_alloc_block_size = 32768

default-storage-engine = innodb

innodb_log_files_in_group=2
innodb_log_file_size=512M
innodb_buffer_pool_size = 6000M
innodb_thread_concurrency=8
innodb_flush_method = O_DIRECT
innodb_file_per_table = 1
innodb_flush_log_at_trx_commit = 2
innodb_additional_mem_pool_size = 20M
transaction-isolation=READ-COMMITTED
innodb_adaptive_flushing_method=keep_average
innodb_flush_neighbor_pages=1
innodb_log_block_size=4096