[OpenAFS] TSM client for OpenAFS

Felix Frank Felix.Frank@Desy.de
Fri, 3 Apr 2009 11:08:52 +0200 (CEST)

On Fri, 3 Apr 2009, Mattias Pantzare wrote:

>>>> Of course, but it will still take up much more space. If we do full dump
>>>> once a week
>>>> and incs each night there will be many duplicates of files changed early
>>>> after the full dump :-)
>>> Do I correctly infer that you don't need a full backup as in "ability to
>>> restore data from arbitrary points in time"?
>> Well, TSM only store one copy of a specific object, while if you do full
>> dumps + incs
>> there will be multiple copies.
> Just to be clear, TSM stores one copy per version of a specific object.
> If we do full dumps + incs we have to have at least two full dumps in
> the backup system at a given time.
> If we do it the TSM way only one copy have to be in the backup system
> if the file is static.
> We do need ability to restore data from arbitrary points in time. (I
> work at the same place as Anders)

For data that is in a regular backup, it would indeed cause overhead to 
exploit RxOSD's HSM backend I think. Its idea is to transparently extend 
available AFS space and keep a safety copy of all current data "for 
free". It is no replacement for a full backup (which I wrongly assumed you 
didn't require).