Dear AFS Contacts --
Transarc has uncovered a problem with AFS 3.4a Backup. The
AFS 3.4a Backup System (build levels 4.39 ["patches"] and earlier)
may fail to back up volumes housed on a multihomed server, because it
does not attempt to fetch from the VLDB all possible IP addresses
associated with the server name in the volume set entry. The defect
number for this problem in 7453, and a fix for it will be included in
the next "patches" release. In the meantime, two workarounds are
available which are documented at the end of this mail.
DOES THIS AFFECT YOU?
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A) If you do NOT have any multihomed fileservers in your AFS cell, this
does NOT affect you. This problem only occurs while trying to backup
volumes on a multihomed fileserver.
B) If you specify '.*' in the "server" field of the AFS Backup
volume-set entries, then this problem does NOT affect you. The "server"
field within the AFS Backup volume-set entry needs to have a server
address or name (of a multihomed fileserver) for this problem to affect
you.
If you do have a multihomed fileserver and if you specify its name
within the "server" field of an AFS Backup volume-set entry, then follow
these steps to determine if the volumes are being backed up.
1. From the AFS Backup volume-set entry, get the name of the
multihomed fileserver from the "server" field. This will be an IP
address or machine-name.
2. Do a listvldb of that fileserver.
3. If the "server" field for the RW site in a vldb entry is the same
as the "server" field within the volume-set entry, then the volumes
are getting backed up.
4. If they are not the same (different names or different IP
addresses), then no volumes from that server are being backed up.
5. If they are the same, Transarc still recommends that you take the
necessary steps outlined in the workaround.
WORKAROUND
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There are two possible workarounds to this problem:
1) Add more entries to the volume set, one for each name or address
associated with the multihomed machine. If (for example) machineX
has an Ethernet address called ether.server and a FDDI address called
fddi.server, you would create entries for:
server ether.server, partition .*, volumes: user.*\.backup
server fddi.server, partition .*, volumes: user.*\.backup
If the different interfaces do not have separate names, then the you
can put an IP address in the "server" field instead.
Note that adding the additional line(s) does not result in volumes being
backed-up twice. There are no known side effects to this workaround.
2) Replace the specific server name in the volume set entry with ".*".
So, for example,
server machineX, partition a, volumes: user.*\.backup
becomes
server .*, partition a, volumes: user.*\.backup
This is the simpler solution, and would be acceptable provided that
there are no volumes stored on partition a of other machines that you
don't want included in this dump set.
Transarc is currently working on a fix which will be available in the
next release of the AFS 3.4a "patches" tree.
As always, contact Product Support with questions.
Kathy Rizzuti
Area Manager, File Systems Support
Transarc Corporation
