Dependencies would be pulled into snapshot:
    [snap1]: Snapshot from mirror [wheezy-main]: http://mirror.yandex.ru/debian/ wheezy
from snapshot:
    [snap2]: Snapshot from mirror [wheezy-backports]: http://mirror.yandex.ru/debian/ wheezy-backports
and result would be saved as new snapshot snap1.
Loading packages (60863)...
Building indexes...
[+] libjson-c2_0.11-3~bpo7+1_amd64 added
[+] libjson-c2_0.11-3~bpo7+1_i386 added
[+] liblogging-stdlog0_1.0.4-1~bpo70+1_amd64 added
[+] liblogging-stdlog0_1.0.4-1~bpo70+1_i386 added
[+] rsyslog_7.6.3-2~bpo70+1_amd64 added
[+] rsyslog_7.6.3-2~bpo70+1_i386 added
[-] rsyslog_5.8.11-3_amd64 removed
[-] libestr0_0.1.1-2_amd64 removed
[+] libestr0_0.1.9-1~bpo70+1_amd64 added
[+] init-system-helpers_1.18~bpo70+1_all added
[-] rsyslog_5.8.11-3_i386 removed
[-] libestr0_0.1.1-2_i386 removed
[+] libestr0_0.1.9-1~bpo70+1_i386 added
ERROR: unable to create snapshot: snapshot with name snap1 already exists