[Box Backup] machinereadble output bbackupquery - help needed

[Chris Wilson]

Hi Pete,

On Sat, 18 Oct 2008, Peter Jalajas, GigaLock Backup Services wrote:

> On Sat, Oct 18, 2008 at 9:43 AM, Chris Wilson <chris@qwirx.com> wrote:
> 
> > I know some people set the soft limit to zero, and therefore only the hard
> > limit is useful to them.
> 
> Now that is fairly fascinating.  I thought setting Soft to zero would
> be just a temporary setting that would be used to clear out your
> store.  Doesn't housekeeping delete files to get the Used down to Soft
> (zero in this case)?  Relevant links:
> http://lists.warhead.org.uk/pipermail/boxbackup-commit/2007-February/000433.html

Not quite. It says "If the soft limit is ... set to zero (to discard all 
old/deleted blocks on every housekeeping run)". This is correct. Setting 
the soft limit to zero ensures that old and deleted versions of files are 
removed, but current files are never removed by housekeeping.

> From http://www.boxbackup.org/trac/wiki/CertificatesAndAccountsManagement :
> The backup client will (voluntarily) try not to upload more data than
> is allowed by the soft limit.

I think that since the above patch was applied, this is now incorrect, and 
in fact it will simply stop adding new files when the server tells it that 
it has exceeded the hard limit. The server will then,

> when doing housekeeping for this account, try and delete old versions 
> and deleted files to reduce the space taken to below the soft limit.

> FWIW, I generally keep a fairly huge gap ("free board?") between my Soft 
> and Hard limits, shooting for 2 or 3 times the size of the largest file 
> (usually a few GB Outlook.pst or Exchange backup file; so I usually give 
> a "free board" between Soft and Hard of 10 or 20 GB)

This is still a very good idea, as recommended in the documentation above.

> my thinking being so bbstored has room to efficiently upload that file 
> and do what it needs to do to make room for it (under the assumption 
> that that "free board" space is used only briefly and that the account 
> usage will fairly quickly [a few hours or under a day?] get back down to 
> the Soft limit).

That is correct ("fairly quickly" being at the next housekeeping run, no 
more than TimeBetweenHousekeeping), provided that the account does not 
store enough current files (not old or deleted) to take it over the soft 
limit. bbackupd will no longer check for this and stop uploading at that 
point.

If this behaviour is undesirable for you then we should look at other 
options, but it is something that you can implement in local policy by 
checking the (machine-readable) output of the usage command on the server 
for each account, and take some human action such as contacting the 
account owner when they exceed the soft limit with current files (to sell 
them more space).

Cheers, Chris.
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