[329] in Athena_Backup_System
Information for you.
daemon@ATHENA.MIT.EDU (Bill Cattey)
Thu Oct 17 17:11:27 1996
Date: Thu, 17 Oct 1996 17:08:51 -0400 (EDT)
From: Bill Cattey <wdc@MIT.EDU>
To: khutchin@lynx.dac.neu.edu
Cc: athena-backup@MIT.EDU
You will get faster response to questions if you raise them to the whole
group. The email list is "athena-backup@mit.edu". I have added you to
the list so you will see information as it goes by.
The athena-backup home page is:
http://web.mit.edu/afs/athena.mit.edu/astaff/project/athena-backup/www/home.htm
l
From there are links to documents that SHOULD be the most up-to-date versions.
On to your questions:
> 1) Can I get printouts of the slave configuration files to verify
> syntax and content?
From delgado:
Here is a dump of a sample configuration file. Note that the data in the
configuration file has to be formatted with one specification per line.
Each line is of the form <parameter> : <value>, with the ':' being
surrounded by spaces.
master_server : ops-5
admin_dir : /var/abs/slavedir
device_name : /dev/rmt/0
device_type : mt
device_online : 0
master_principal : abs
slave_principal : abs
> 2) When is ABS run, executed, used? (one time only, daily, on an
> as-needed basis)
From ted:
From the question, I think I need to include some background.
A backup system is something that, in its regular use, is thought of
as running continuously. A backup set is a copy of various file
system data made at a certain time. The backup system has the task of
making sure that backup sets are made periodically. Whether those
sets are made daily, weekly, millenially, is entirely up to the
administrator who configures the backup system. The administrator
also needs to decide how long to keep the backup sets.
In my experience, the usual configuration is for there to be three
different types of backup sets. The first type is for the normal
day-to-day maintenance of the system. It usually has a daily or
weekly period and usually includes all of the file system data that
anyone might want backed up. It is used to protect against the
catastrophic loss of data in the file system. Backup sets in this
category are usually only saved a few months before they are
considered too old to be useful.
The second type is for long term maintenance of the system and also
includes all of the file system data. It is usually done 2-4 times
yearly and protects against data loss due to the slow evolution of the
file system (i.e. changes wrought through normal use). These types of
backups are usually referred to as archives and mostly kept for as
long as the backup media can be used, usually several years. The only
real differences between the first and second types are in how the
backup media is treated after the backup set is made and also in the
period involved. This type of archive set is usually scheduled by
hand. In other words, the backup system is told to run this type of
set at a time chosen by the administrator once the administrator
decides it is time.
The third type of backup set that I usually see is also referred to as
an archive and kept for as long as the backup media lasts. However,
this type of backup set is different in that it only includes a
certain type of data in the file system - data that is about to be
deleted because it is no longer in use. Usually this data belongs to
users who are no longer part of the system. This type of backup set
usually needs very close attention by the administrator and is
certainly only scheduled when the administrator decides. A small,
slowly evolving file system may never need to use this type of backup
set. A large, quickly evolving one may need this multiple times a
year.
That answers the question on one level - that of creating the backup
sets. As to when the backup sets get used, the short answer is:
whenever data is lost from the file system and needs to be recovered.
If everything were perfect, this would be never. In practice, it
depends on the size and usage of the system. In our case, it is
usually necessary to recover data from some backup set, on the
average, at least once a week.
The short answer is that ABS will be used continuously (or daily) to
create backup sets and that ABS will need to restore data from these
backup sets as needed.
The extremely short answer is: daily.
> 3) Can I get printouts of the main screen?
From delgado:
We have available only the tcl shell right now. After we get
the secure web working we should have more menus available
for viewing.
From wdc:
This probably means we should make some transcripts or terminal logs and
provide them to Karlyne.
> 4) Can I get information about configuring the master that is similar
to the information about configuring the slave?
From delgado:
This is a sample configuration file for the master. It has the same
format for that of the slave:
default_error_delivery_service : zephyr
default_error_delivery_destination : delgado
auto_labeling : 1
slave_register_file : /var/abs/device_reg
queued_job_mode : 1
There are also a few additional command line options for the master:
-u <oracle-user-name> this is the name of the oracle user that the master
will connect to oracle as
-p <oracle-password> this is the oracle password that the master supplies to
oracle when it connects to the database.
-k <kerberos-princ> this is the name of the kerberos principal the
that master
"runs as" for authentication purposes.
>
> 5) Can I see the ABS in use to get a feel for how a system
> administrator would use it and how the application is used?
From delgado:
If we get her an athena account I can add her to the list of
authorized users. We might want to schedule a time where
she can come in and we can "introduce" her to it.
> I can come to your office after work this week to pick up the screen
> prints of the slave configuration files. I will then try to document
> the procedures for configuring a slave using FrameMaker. After I
> finish, I can give you the file for a technical review and to check for
> compatibility with your system.
It looks like we have the example Master and Slave configuration files
enclosed in this note.
If we get that transcript of the ABS terminal session, we can email that
to you.
In any event, Diane, Ted, and I are available to meet with you as needed
after-hours. Diane is available Wednesdays or Fridays with advanced
planning.. I'm pretty much working here between 5:00 and 7:00 PM
anyway. Ted can schedule on a case-by case basis.
