[256] in Athena_Backup_System
Re: Revised requirements
daemon@ATHENA.MIT.EDU (delgado@MIT.EDU)
Tue Jun 11 12:15:39 1996
From: delgado@MIT.EDU
To: Bill Cattey <wdc@MIT.EDU>
Cc: athena-backup@MIT.EDU
In-Reply-To: Your message of "Mon, 10 Jun 1996 20:28:21 EDT."
<Qlj=qZUGgE6e1JzJ00@mit.edu>
Date: Tue, 11 Jun 1996 12:15:29 EDT
> 2) The system shall be able to perform dumps of limited functionality
> when the database or Master is offline through the use of a Crippled
> Mode user interface client. At minimum, the Crippled mode dump
> command will prompt for a server name, and dump all partitions and
> volumes from the named server.
This requirement should state whether we are also supposed to provide
the ability for the administrator to specify use of rw or cloned
volumes for AFS filesystems. For AFS, we don't want to really be
dumping all volumes; we should dump all rw volumes or all cloned
volumes.
> 5) The correlation information of the tape to volume and tape to
> partition required for restores will be provided by an ASCII
> report that is produced as part of periodic maintenance
> procedures.
Technically, we don't keep tape to partition information. We keep tape
to volume information (when did this tape to partition stuff get added?).
Not all dumps are dumps of partitions. We can derive some relationship
between tapes volumes and the servers they live on. For AFS, We keep only the
server/partition info for a volume for the most recent time that its
dumpset was last synched up.
> 7) In the event that dump service of finer granularity than a whole
> server (i.e. a partition or collection of volumes), the mechanism
> developed for determining which volumes to dump will take care to
> notice volumes created on a file server subsequent to the crash
> of the Master.
I don't really understand this. It is too vague to be implemented.
>Jeff says crippled mode should only write onto blank tapes. He doesn't
>even want a utility to make tapes pretend they're blank.
Jeff is out of luck. the "mt" command suite for tape manipulation which
comes with the operating system provides this functionality. I use it all
the time to help simulate larger tape pools than what I have.
>Diane, Brian: Could you correct me on what status should be retained?
For each tape in the tapeset:
- date of dump
- level of dump
- dump since date for level > 0 (dump all files changed since "date")
- internal tape id
- external tape id
- dumpset instance
- dumpset name
Volume/Tape mapping info:
abs volume id
tape external id
position on tape
size of volume at dump
You will additionally need to keep track of the AFS volume ids, names,
servers, cell, and paritions, so that the tools can create new
volume entries for any new volumes which were picked up in the crippled
mode. You will also need to indicate what pool the tape belongs to because
a tape record will need to be created as well. The tool will also
have to create a dumpset entry for this stuff, but that is not difficult.
I believe this is all. If I think of anything else, I'll let you know.
