SQLite and ext3 journalling mode
Ric Wheeler
rwheeler at redhat.com
Wed Dec 8 13:26:27 UTC 2010
On 12/08/2010 02:02 PM, Miller, Mike (OS Dev) wrote:
>
>> -----Original Message-----
>> From: ext3-users-bounces at redhat.com [mailto:ext3-users-
>> bounces at redhat.com] On Behalf Of Ric Wheeler
>> Sent: Wednesday, December 08, 2010 11:08 AM
>> To: Richard Hipp
>> Cc: ext3-users at redhat.com
>> Subject: Re: SQLite and ext3 journalling mode
>>
>> On 12/08/2010 11:56 AM, Richard Hipp wrote:
>>>
>>> On Wed, Dec 8, 2010 at 11:25 AM, Ric Wheeler<ricwheeler at gmail.com
>>> <mailto:ricwheeler at gmail.com>> wrote:
>>>
>>> On 12/08/2010 06:52 AM, Dan Kennedy wrote:
>>>
>>>
>>> Thanks. But to be clear, is data=ordered better than
>> data=writeback
>>> wrt. data integrity following a power failure?
>>>
>>> Regards,
>>> Dan.
>>>
>>>
>>> Data integrity can mean a couple of different things.
>>>
>>> If you are file system meta-data centric (i.e., a file system
>> developer or
>>> just worried about having to run fsck after a crash to repair the
>> file
>>> system), then both options *should* be equivalent.
>>>
>>> If you are one of those annoying users who define data integrity
>> to
>>> include those annoying details like will my file have garbage in
>> it after
>>> a crash that will make my DB or other app puke, then data ordered
>> is
>>> clearly more robust.
>>>
>>>
>>> Thanks, Ric. Yes, we are numbered among the "annoying users". Based
>> on what
>>> you are telling us, we'll recommend that people use data=ordered,
>> barrier=1
> Just as an FYI, not all HW vendors enable the drive write cache especially on array controllers. In those cases barriers do nothing.
>
> -- mikem
>
>
Right - upstream has been working to make sure that we can default to barriers
on and not see a performance hit for devices like arrays that don't need them ...
Ric
More information about the Ext3-users
mailing list