On Tue, Aug 27, 2019 at 12:26 PM Wido den Hollander <w...@42on.com> wrote:
>
>
>
> > Op 27 aug. 2019 om 11:38 heeft Max Krasilnikov <pse...@avalon.org.ua> het 
> > volgende geschreven:
> >
> > Hello!
> >
> > Sat, Aug 24, 2019 at 10:47:55PM +0200, wido wrote:
> >
> >>> Op 24 aug. 2019 om 16:36 heeft Darren Soothill <darren.sooth...@suse.com> 
> >>> het volgende geschreven:
> >>>
> >>> So can you do it.
> >>>
> >>> Yes you can.
> >>>
> >>> Should you do it is the bigger question.
> >>>
> >>> So my first question would be what type of drives are you using? 
> >>> Enterprise class drives with a low failure rate?
> >>>
> >>
> >> Doesn’t matter. From my experience: With 2x replication you will loose 
> >> data at some point.
> >>
> >> As a consultant I have just seen too many cases of data loss with 2x.
> >>
> >> Please, don’t do it.
> >
> > I'd like to ask: do the new features like checksumming fix this problem?
>
> No, they don’t.
>
> Imagine you take a machine down for maintenance and while that machine is 
> down you loose a disk.
>
> You lost data. Although you can bring back the other machine you are still 
> missing transactions.
>
> This is not fictional, this happens.

100% agree, this happens *all the time* with min_size 1.

If you really care about your data then 2/1 just doesn't cut it.


Paul

>
> Same as that during the backfill of a disk you just lost the disk with the 
> remaining copy dies under the load of the backfills.
>
> I have seen this happen too many times in the last years.
>
> Don’t try to cut corners.
>
> Wido
>
>
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