Hi,
We would like to solicit the opinion of the OpenAFS community on what status
vos should return for pre-attached volumes.
The demand-attach file-server introduces a number of volume states that vos is
currently unable to transparently report. Instead, it simply returns on-line or
off-line. The following comment details when the volume is reported as off-line:
/* Conditions that offline status is based on:
volume is unattached state
volume state is in (one of several error states)
volume not in service
volume is not marked as blessed (not on hold)
volume in salvage req. state
volume needsSalvaged
next op would set volume offline
next op would not leave volume online (based on several conditions)
*/
otherwise, it is reported as on-line. The conditions above follow the general
(mis-)perception that volumes with an off-line status are in error.
The question concerns the status reported for volumes that are "pre-attached".
These are volumes that the file-server hasn't fully attached because they
haven't been accessed (or attached and subsequently un-attached because they
haven't been accessed in a certain period of time). Currently, these volumes
are reported as on-line, since they aren't in error. However, we believe that we
need more informative reporting for these volumes for a number of reasons:
* strictly speaking, the volumes aren't on-line
* there are a number of ways to determine pre-attached volumes (dump the
file-server state, fssync-debug, ...), but all need to be executed locally on the
file-server
* pre-attached vs attached state is interesting, since it helps determine
exactly what percentage of volumes on a file-server are actually in use
There are at least four options:
1. expose all underlying states to vos examine
2. expose pre-attached to vos examine
3. convert pre-attached to on-line for vos (the current behavior)
4. convert pre-attached to off-line for vos
Option 3 is currently implemented and is the least desirable.
Our suggestion is that we implement option 1, which will require exposing the
current volume state onto the inUse field in the FillVolInfo function in the
volserver. The vos command would need to be modified to be aware of the new
values, but unmodified vos commands would report off-line for volumes in a
state other than fully attached.
Note that options 1 and 2 involve a change in behaviour for sites running
demand-attach.
Comments, concerns, agreement?
ali
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