Re: fsck w/out delete privilege

[Colin Percival <cperciva@tarsnap.com>]

Gleb Arshinov wrote:
> On Thu, Apr 29, 2010 at 3:52 PM, Colin Percival <cperciva@tarsnap.com> wrote:
>> Gleb Arshinov wrote:
>>> Any update on releasing this?
>> That's coming in tarsnap 1.0.27, which will be out Real Soon Now.  Sorry
>> about the delay -- I've been working on back-end server performance and
>> the client code got stalled for a while.
> 
> That's great to hear.  Both that fsck is coming and that progress on
> tarsnap continues.

Aside from occasional consulting gigs, I'm working on Tarsnap full-time -- not
always on the client side, of course.

> Now, and taking off my early adopter hat, and putting on the business
> hat: It may be less efficient but just doing fsck on public machines
> is easier to automate than copying cache from central machine.
> Building automation is expensive.

Sure.  I just wanted to provide some extra information to help guide those
decisions -- it's up to you whether you take the easy but less efficient
route or the more complicated but more efficient route. :-)

> Btw, one use case where read-only fsck will actually add efficiency is
> reporting.  We'll want to monitor backups from the private machine,
> and getting stats there requires up-to-date cache, and getting that
> cache currently invalidates caches on public machines.  I'd imagine
> with read-only fsck that will not be the case.

Hmm, interesting point.  As it currently exists in my tree, read-only fscks
still invalidate the cache (I'm implementing a read-only fsck as a transaction
which doesn't write or delete any blocks).  I could change this, but it would
involve a rather significant rewrite of that code.

Can you elaborate on why you need the cache in order to monitor machines'
backups?  You can run --list-archives, -t, and -x without a cache directory,
and you can see statistics on bandwidth and storage usage via the web interface,
so I'm not sure what exactly you're getting running --fsck.

-- 
Colin Percival
Security Officer, FreeBSD | freebsd.org | The power to serve
Founder / author, Tarsnap | tarsnap.com | Online backups for the truly paranoid