[ZODB-Dev] Repozo tests -- not

Daniel Kraft news at spotlite.de
Tue Dec 8 17:21:52 EST 2009

Jim Fulton wrote:
> On Tue, Dec 8, 2009 at 1:49 PM, Benji York <benji at zope.com> wrote:
>> Any incomplete writes that are in progress at the time of the copy will
>> simply be ignored when the resulting backup is opened later.
> Note that this assumes that you are using a straightforward linear copy.
> rsync would likely produce unpredictable results.

Every modern volume manager or whatever supports snapshotting a
filesystem. A snapshot is a good-enough synchonous copy. You simply
store its contents to somewhere and you're done, even with blobstorage.

At least that's what we do, because repozo kills our netapp cluster and
disconnects ISCSI volumes due to its usage of sync disk i/o (the latter
is only 90% verified).

Even, with snapshots we have 0% cpu load on backup. With repozo we have
100% iowait for a long time.


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