[Technical] Sonasoft?

[Clark, Ian C]

> -----Original Message-----
> From: tech-bounces at edulists.com.au [mailto:tech-
> > Any area of computing that has transactions (and it can be kernel
> > processes or a web database) needs concurrency control.
> 
> For transactions, then yes, I agree. But for Word and Excel files? No.

The classic interceding update problem still applies, Con. In a network,
there can be concurrent access of a document. What happens when two
people open the same spreadsheet and work on it?

One of them (the first person to save) is going to be very disappointed
with what they find the next day. The last person to save is just going
to shrug their shoulders, I suppose.

I remember reading a post by an upset Linux admin that he had got file
locks going in Samba, and OpenOffice honoured them but KOffice and
(IIRC) Gedit simply ignored them. The OS - which remember has the job of
refereeing between processes on a computer - refused to impose order on
the situation.

> And it's useful in certain circumstances. But why file-lock almost
> every file access?

I'll explain this slowly. It's not the OS that applies or removes the
file lock on a document.

It's the application.

It is your fellow developers, who understand the app they have written
and its capabilities, that decide to code a lock or not.

The OS merely respects the developer's wishes (or not, in the case of
most *nix systems).

>  Sure, it's not advisable to do file backups on an active,
>  in-transaction server, but that's another story.

But that's all the Cybersource 'Datasafe' device is - a file level
backup server, that doesn't understand the inner goings-on of an
application, that can't back up a working Linux or Windows environment.
There's no point pretending otherwise. 

> What a Datasafe _does_ give you is an archive to every version of
every
> document and (non SQL Server, non Exchange) datafile that you care
> about. And this happens automatically.

Well, clearly not for any documents in use. Or video files of over 1Gb.
Or *any* operating database. The PostgreSQL and MySQL manuals warn
specifically against the file level backup your Datasafe does.

> Do you have a cost estimate for:
> 
>  1. The cost of a tape drive that can hold say 400GB &
>  2. The cost of 21 400GB tapes to hold a month's worth of backup?

Con, your device isn't capable of a 400Gb daily backup. 

According to your own documentation, it would take 3.3 days to do one
night's worth.

For $5000 (clearly, this is not the model the poor souls in the shop get
with your $10,000 three server setup), the customer only gets 480Gb of
capacity on the device anyway!

Overall, I can't help but be fascinated by your defence of the
indefensible. I don't have a problem explaining the advantages and
shortcomings in any of the products I'm a dealer for - Alloy networking
stuff, and nor do I advertise them in forums. That might make me a lousy
salesman, but as a freelance consultant it also makes me an honest
disseminator of information to the public.

Cheers,
Clarky
 









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