Changes between Initial Version and Version 2 of Ticket #600


Ignore:
Timestamp:
2013-07-17T13:45:32Z (11 years ago)
Author:
daira
Comment:

I'm not sure this ticket is any longer relevant for the leasedb branch. Brian?

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  • Ticket #600

    • Property Keywords storage disk-backend performance migration crawlers brians-opinion-needed added
    • Property Owner set to warner

  • Ticket #600 – Description

    initial v2  
    1818
    1919There is a certain amount of metadata associated with each bucket. For
    20 mutable files, this includes the write-enabler. Both mutable and immutable
    21 files contain lease information. To make share-migration easier, we decided
    22 to make the share files stand alone, by placing this metadata inside the
    23 share files themselves, even though the metadata is really attached to the
    24 bucket. This unfortunately creates a danger for mutable files: some of the
     20mutable files, this includes the write-enabler. [edit: Both mutable and immutable
     21container files used to also contain lease information at the end of the
     22file, but that is no longer true on the leasedb branch which will be merged
     23soon.]
     24
     25To make share-migration easier, we originally decided to make the share files
     26stand alone, by placing this metadata inside the share files themselves,
     27even though the metadata is really attached to the bucket.
     28~~This unfortunately creates a danger for mutable files: some of the
    2529metadata is located at the end of the share, and when the share is enlarged,
    2630the server must copy the metadata to a new location within the file, creating
    27 a window during which it might be shut down, and the metadata lost.
     31a window during which it might be shut down, and the metadata lost.~~
    2832
    2933Since we might want to add even more metadata (the other-share-location