[nailgun] Split diagnostic snapshot into manageable chunks

[Dmitry Pyzhov]

Sometimes diagnostic snapshot became huge and in order to share it it should be split. Files should be less then 5Gb in order to upload to cloud storages.

Also we should investigate if we can add ability to skip some files from snapshot or split it into several parts based on directory structrure.

[Dmitry Pyzhov (dpyzhov)]

This issue can be solved in blueprint https://blueprints.launchpad.net/fuel/+spec/manage-logs-with-free-space-consideration

[Alexander Bozhenko (alexbozhenko)]

In the end of creation diagnostic snapshot we have:
Trying to execute command: tar zcf /var/www/nailgun/dump/fuel-snapshot-2015-04-09_04-06-50.tgz -C /var/www/nailgun/dump fuel-snapshot-2015-04-09_04-06-50

We can add an option to change it to something like:
tar zcf - -C /var/www/nailgun/dump/ fuel-snapshot-2015-04-09_04-13-17 | split --bytes=200MB - fuel-snapshot-2015-04-09_04-13-17.tgz

To archive it:
cat fuel-snapshot-2015-04-09_04-13-17.tgz* | tar xz