Hello Joe,
Monday, February 23, 2009, 7:23:39 PM, you wrote:
MJ> Mario Goebbels wrote:
>> One thing I'd like to see is an _easy_ option to fall back onto older
>> uberblocks when the zpool went belly up for a silly reason. Something
>> that doesn't involve esoteric parameters supplied to zdb.
MJ> Between uberblock updates, there may be many write operations to
MJ> a data file, each requiring a copy on write operation. Some of
MJ> those operations may reuse blocks that were metadata blocks
MJ> pointed to by the previous uberblock.
MJ> In which case the old uberblock points to a metadata tree full of garbage.
MJ> Jeff, you must have some idea on how to overcome this in your bugfix, would
you care to share?
As was suggested on the list before ZFS could keep a list of freed
blocks for last N txgs and if there are still other blocks to be used
it would not allocated those from the last N transactions.
--
Best regards,
Robert Milkowski
http://milek.blogspot.com
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