SQLite and ext3 journalling mode
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
>>> wrt. data integrity following a power failure?
>>> 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
>>> system), then both options *should* be equivalent.
>>> If you are one of those annoying users who define data integrity
>>> 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
>>> 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,
> 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 ...
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