[OpenAFS] Understanding questions backup volume
Thu, 09 Feb 2006 13:35:21 +0100
Frank Burkhardt wrote:
>>At least a RO copy could be converted to a RW volume in nearly NO time,
>>but a backup volume?
> A backup volume can't because it's stored as a diff against the RW which means,
> it's damaged when the RW is.
As it stands this is incorrect: at the time of the clone a backup
volume *is* the R/W volume (in the sense that its vnode files point to
exactly the R/W's vnodes). It is when files on the volume change
*they* are copied to new vnodes (here multi-GB file begin to become
cumbersome). In that sense the R/W is stored as a diff to the backup,
but with several clones you'd call this something else.
Conceivably however you could have a healthy backup volume and all
files in the R/W somehow damaged (those modified since the clone). In
that case it might make sense to "convert" the backup to a R/W. 'vos
dump|vos restore' should do if you're prepared to pull out the hammer.
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