[ZODB-Dev] Anybody using ZODB with no calls to fsync in production?

[Chris Withers]

+1 from me too, this feels like a really good proposal :-)

Chris

Jim Fulton wrote:
> +1
> 
> Lennart Regebro wrote:
>> On 10/11/06, Roché Compaan <roche at upfrontsystems.co.za> wrote:
>>> http://mail.zope.org/pipermail/zodb-dev/2004-July/007682.html
>>
>> I read this thread, and it seems to me that the ultimate solution
>> would be to have a setting for FSStorage, say "fsync-behaviour" with
>> the options of "single", "double", "none" or "interval". We'd need an
>> explaining text too. Something like:
>>
>> fsync-behaviour: Determines when fsync is called. Default: single.
>>
>> Options:
>>
>> Single: Calls fsync once per transaction. Gives you reasonable data
>> reliability in most cases. You should in a crash only lose one
>> transaction.
>>
>> Double: Calls fsync before marking transaction as complete as well as
>> after marking it as complete. This setting is only useful if you have
>> configured the complete storage chain (operating system, filesystem,
>> drivers, controllers and disks) will not let fsync return until data
>> is safely and completely written to disk. In most cases and without
>> configuration of the complete storage chain, this setting will slow
>> down FSStorage without actually increasing the reliability of data
>> written to disk.
>>
>> Interval: Will call fsync only every couple of transactions, with the
>> interval determined by the setting "fsync-interval". This is good for
>> write-intensive applications where you don't mind loosing a couple of
>> transactions if the computer should crash.
>>
>> None: Will never call fsync. Good for applications of high write load
>> where the data is not critical. Never ever use this setting on
>> windows, as it on windows makes it highly likely that data will not be
>> written to disk at all, and a crash could quite likely make you loose
>> all your changes.
>>
> 
> 

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