[Box Backup] A few questions about BoxBackup

[Ben Summers]

On 15 Feb 2005, at 09:04, Gary wrote:

> Hi,
>
> A few questions about BoxBackup:
>
> 1. One-time backup. Is there any way to backup a set of files on the
> bbstored side, erase them locally, but instruct bbstored NOT to delete
> those files on housekeeping? I have some files that I do not want to
> keep around my server, but would like to store them in the encrypted
> form on a remote machine. Perhaps an option in bbackupd.conf along with
> a way to later on remove an archive selectively?

No. This would not do what you want anyway, because the keys to decrypt 
the files are on the local machine. Therefore anyone with sufficient 
access to the local machine would be able to download the "encrypted" 
files. For someone on the local machine with access to the keys (ie 
root or physical access to the box), the files on the store should be 
considered in plaintext when evaluating security.

>
> 2. Immediate clean-up of deleted files. I understand that bbstored will
> keep deleted files for as long as the soft limit is not hit. Is there
> any way to instruct bbstored to remove deleted files from the store on
> the next housekeeping run, without waiting for the soft limit?

There is support for this on the server, however, there is currently no 
user interface to it.

>
> 3. Compare -aq reliability. Does bbstored actually fully re-create a
> tested file (from multiple uploaded rsync "slices"?) before calculating
> its checksum and sending it back to the client? In other words, is -aq
> comparison end-to-end (attributes aside)?

bbstored cannot recreate the files, because it does not have access to 
the keys. What it does is simply send the encrypted checksums that the 
client sent it the last time it was uploaded -- no processing is done 
on the server. It will send one checksum per block in the file, because 
that is the unit in which is it compressed and encrypted.

>
> 4. Compare -aq performance. I ran some tests on the compare command
> bbackupquery, and even on a set of 65 very small files (around 200 Kb
> each) in 11 folders, compare -aq tool well over 5 minutes. It seems a
> bit on the slow side, considering the network link is ~1Mb/sec. Is this
> normal?

It sounds a little slow to me. A few things, off hand, which could 
affect this are:

* the load on the client and server
* the latency of your network link
* the usage of your network link -- is something uploading or 
downloading stuff? Maybe a backup is ongoing?

And if it's ADSL, one direction will be slower than the other.

It would be interesting to turn on extended logging on the client and 
server, and see what exactly it was sending, and when.

Ben