Re:[Prevayler-discussion] Dual Logging

[Klaus W. <kl...@bo...>]

> BTW, does anyone actually use the possibility of 
naming more than one 
> logging directory in the SnapshotPrevayler constructor 
(which splits, 
> not replicates the logs)? To me, this strongly smells 
like a solution to 
> a non-problem :)

Consider a single huge atomic command that takes several 
seconds to serialize. You cannot block the whole system 
to do that.

But I would also like to know if anyone is using/would 
really use that. The problem is that is still in the 
alpha version...

See you, Klaus.


> 
> ---------- In=EDcio da mensagem original -----------
>      De: prevayler-discussion-
ad...@li...
>    Para: pre...@li...
>      Cc: 
>    Data: Tue, 05 Nov 2002 01:23:35 +0100
> Assunto: [Prevayler-discussion] Dual Logging
> Hey, the list's been really quiet these days...
> 
> What I'm thinking about today is a mechanism to write l
ogs to more than 
> one directory at a time.
> 
> The setting: I have a webserver with two hard disks. Th
e second disk is 
> used as a backup medium. Currently I'm .tar.gz-
ing the whole 
> PrevalenceBase directory every hour and store the archi
ve on the second 
> disk. A suboptimal solution to say the least.
> 
> What I would like Prevayler to do is automatically writ
e command logs to 
> both disks. This way, there's always an up-to-
date backup. Snapshots 
> should also be written to both disks. It would be perfe
ct if it worked 
> like this: After writing a snapshot (if there wasn't an
 exception!), all 
> previous snapshots and old command logs on disk 1 are d
eleted. On disk 
> 2, they remain. Thus, disk 1 always contains the minima
l set of files 
> necessary to restore the database. Disk 2, on the other
 hand, holds a 
> complete history of the database, allowing to recover p
revious states.
> 
> So on the API side, we need:
> -Specification of multiple snapshot+logging directories
> -A "keep history" flag for each directory
> 
> Any thoughts on how to add this most elegantly?
> 
> BTW, does anyone actually use the possibility of naming
 more than one 
> logging directory in the SnapshotPrevayler constructor 
(which splits, 
> not replicates the logs)? To me, this strongly smells l
ike a solution to 
> a non-problem :)
> 
> -Stefan
> 
> 
> 
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