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Collaborative Computational Project Number 14

for Single Crystal and Powder Diffraction


Routine Backing and Archiving of the CCP14 SGI O2-IRIX Web Server onto DDS3 DLT DAT Tape using XFSDUMP

The CCP14 Homepage is at http://www.ccp14.ac.uk

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[Aims | Present Strategy | Software Options for Tape Backup | Installing the DAT drive under SGI IRIX 6.5.x] Backup Method and Practises]


Non-standardisation seems to be the rule when UNIX tape backup software and systems. Thus it looks like tape backup with UNIX is a pain as if lucky, when backing up with XFSDUMP (preferred option) only another SGI with IRIX 6.5.x can recover the tapes.

For archiving, non-compressed drives are used as even with compression, the web_disc will not fit on a single tape. So may as well minimise complications for disaster recovery by not having compression.

Present Strategy (late October 2000)

  1. Rsync the crystallographic and /usr/local areas to the secondary 50 Gig backup disk
  2. Backup 50 secondary disk onto DDS3 Tape (presently ~ 18 Gig: Primary 75 Gig disk has a total of 44 Gig used - most of which are non-crystallographic mirroring)

Software Options for Tape Backup

Commercial options exist but they seem more based on network backups rather than a local disk on a single server to a local tape drive.

Installing the Seagate Scorpion 24 DAT Driver under SGI IRIX 6.5.x

Hardware and various device options that can be activated by writing to the device names in /dev/rmt

Backup Method and Practises

Summary: A script using xfsdump is used to do a full backup of the system (tapes stored on-site and off-site) followed by a daily level 1 incremental backup onto single tapes. During level 1 backup, iImportant files are "touched" so they will be retrivable from any level 1 tape.

XFSDUMP seems the most appropriate for backing a stand-alone system as other systems are made more for network backup and require deamons to be running that are not neccessary in this case.

The scripts are based on ones provided by Brent Bates - http://www.vigyan.com/~blbates/

Scripts used to do backup of CCP14 Area

Rsync disk mirroring script

Tape Backup Scripts

Bug Fixes

Refer: http://support.sgi.com/surfzone/content/bugs/html/incidents/641000/641606.html
Xfsdump silently misses files.

Bug Number           : 641606
Product              : Performance Co-Pilot
Fixed-in Release     : 6.5.6
IRIX Release         : 6.5.2m
Category             : software
Classification       : bug
Priority             : 2
Status               : closed
Date Opened          : 10/09/98
Date Updated         : 08/31/99
Summary              : Xfsdump silently misses files.

Description          : 

If a file is modified while xfsdump is running, the dump can fail 
for that file. The file appears in the dump listing, but the file 
contents are not in the actual dump. No error is reported when 
this happens. 

Fix Information      :

This problem has been fixed in IRIX 6.5.6. Any file that existed all 
through the xfsdump run is now guaranteed to be in the dump. If a 
file is modified during the dump, some version of the file is included 
in the dump. Note that it is not possible for all xfsdump to accomodate 
all scenarios, such as destroy/recreate sequences.

DISCLAIMER: The version with this fix may not have been released yet. 
It is a possibility although unusual that a bug fix may be backed-out 
from the version prior to release. 

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