Problems with dump and restore
Adam Vande More
amvandemore at gmail.com
Tue Aug 12 20:32:34 UTC 2014
On Tue, Aug 12, 2014 at 3:14 PM, Andrew Hamilton-Wright <
AHamiltonWright at mta.ca> wrote:
> Sorry, a bit of a follow up after some reading, as the soft-update
> bit was itching in my memory...
> On Tue, 12 Aug 2014, Roland Smith wrote:
> In 2011, a problem was found with snapshots in combination with soft
>> updates *and* journaling (SU+J) hanging the machine. At that time the
>> recommendation was to switch off journaling.
>> According to https://wiki.freebsd.org/NewFAQs:
>> If you want to use snapshot (dump -L) then disable the soft updates
>> journal for that filesystem.
> I have just realize that the soft update journal (newfs option -j enable)
> is actually not in play here, however "soft updates" (option -U) is. My
> understanding of the referenced bug:
> is that it is specifically referred to _journaled_ soft updates as being
> a danger, but soft updates using -U are not referred to by this bug.
> Is that your understanding as well?
> I believe that when I set up the filesystems for this machine in the first
> place, I specifically ensured that "-j disable" was chosen, for exactly
> this reason -- however my logbook does not contain enough detail for
> me to be sure.
> To be clear then, do I understand that your filesystem options include
> neither "-j enable" nor "-U"?
As stated in the bug, only SU+J needs disabling for live dumps. However,
since the bug doesn't even apply to your situation, this is a red herring.
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