[plug] Constant rsync'ing...

[Trevor Phillips]

On Thursday 13 March 2003 17:56, James Devenish wrote:
>
> If you ask a question like "triggered by the filesystem itself" without
> describing what operating system, hardware platform, and filesystem you
> are using then you are surely indicating to us that you want answers
> about the Linux/i386/ext2 combination. I don't know about that.

Sorry. Linux/i386/ext3 - although the FS format is negotiable. I'd prefer a 
solution that works per-directory, rather than per-partition, but I'll still 
consider a per-partition solution if it's worth it.

> In the case of the latter, I will *again* mention that Unison fits this
> bill. In fact, I imagine it can do the former if you disable 'fastcheck'
> (but obviously that means it has to compare file contents on both
> machines and that would be slow). Fastcheck could potentially overlook
> changes (unlikely unless you actually set out to thwarte it), though it
> always does a 'safe check' before overwriting any files with supposed
> "new" versions.

I considered Unison, and keep meaning to try it out in this role. Would it 
really be any faster than rsync's "building file list" phase, though?

One of the complications is this isn't just 2 machines - it's a cluster of 3, 
and so the changes need to be replicated from one primary server to 2 other 
machines. This is part of the problem with rsync - it does the "building file 
list" twice on the current "server", to replicate to both the other machines 
acting as clients.

A "find /top/directory" takes about 30 seconds to run (and finds, for one of 
the directories, over 154 thousand files).

I should set some time aside to grab a coupla PCs and try mirroring of the 
same quantity of files between them using different techniques...

On Monday 17 March 2003 13:00, Tony Breeds wrote:
>
> For 2.4 series kernels look at intermezzo.  It's not 100% of what you're
> after but I think it'll comes close enough.
>
> http://www.inter-mezzo.org/  for mor info.

Intermezzo looks cool and scary. ^_^

It looks more like what I had in mind, although it does operate per-partition, 
which would require a considerable change in structure.

Somewhat related to Intermezzo - does anyone know if it's possible to rescale 
a loop-back filesystem semi-dynamically? eg; You create a 100Mb file, ext3 
it, Intermezzo it, then 3 months later decide it'd be better to have it 
200Mb. Any way to "parted" the file (short of creating a new one of the new 
size, duplicating content, etc...)? ^_^

-- 
. Trevor Phillips             -           http://jurai.murdoch.edu.au/ . 
: Web Technical Administrator     -          T.Phillips at murdoch.edu.au : 
| IT Services                        -              Murdoch University | 
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