[Box Backup-dev] Soft-RAID support

[Chris Wilson]

Hi David,

On Mon, 1 Jun 2009, David Sommerseth wrote:

> I was reading through the BoxBackup documentation, and one crucial point 
> of why I chose BoxBackup seems to change ...
>
> "The server currently supports a kind of RAID 5 in userland for extra 
> reliability. It is designed to use three separate paths which are 
> mounted from three separate physical disks (not partitions on the same 
> disk!). This is deprecated and will be removed in a future version. We 
> recommend that you disable it instead, otherwise you may lose your 
> stored data when this feature is removed. " 
> http://www.boxbackup.org/trac/wiki/ConfiguringAServer
>
> Is there any reasons this will be changed?

Support for it was never finished (no recovery procedure), it is pretty 
limited (only supports RAID 5 and three devices) and it was written at a 
time when OS/software and hardware RAID were not as ubiquitous or well 
supported as they are now.

I can see your point about the usefulness of this for distributed 
encrypted backup. However I'm not convinced about the overall merits of 
storing the data in three separate locations. It's already encrypted to 
the point where a server compromise could get virtually no useful 
information out of the backups. You could achieve what you want with 
distributed OS-level RAID on iSCSI, ATA over Ethernet or NBD devices.

> I evaluated BoxBackup and set it up before this part of the 
> documentation changed.  Anyhow, there's also a contradictory sentence 
> later on in the same URL:
>
> "NOTE Running the server in non-RAID mode has not been tested as 
> extensively as in RAID file mode."

Strictly speaking, in my mind, this is not contradictory as it doesn't say 
that userland RAID is better or recommended, just more tested. However I 
think it may no longer be true. I suspect that few people are using the 
userland RAID feature in production. If anyone except David is, please 
speak up!

Cheers, Chris.
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