[zfs-discuss] ZFS and Power Loss

nick pitlosh via zfs-discuss zfs-discuss at list.zfsonlinux.org
Tue May 5 17:05:28 EDT 2015


It's almost certainly the zil. All other writes are sync anyway if he's
using vmware.
On May 5, 2015 4:54 PM, "Blake Dunlap via zfs-discuss" <
zfs-discuss at list.zfsonlinux.org> wrote:

> The better question here is, what is the actual architectutre top to
> bottom, and does it actually support write integrity. Even if the
> application is terrible, as long as the data is hitting a write call
> to the filesystem "sync=always" should be sufficient. Do they actually
> know its even hitting a write call at this point, or is this a
> pointless rat hole. Was there zfs reported errors, did files on disk
> not match expectations, etc?
>
> -Blake
>
> On Tue, May 5, 2015 at 11:30 AM, Hajo Möller
> <zfs-discuss at list.zfsonlinux.org> wrote:
> > On 05/05/2015 08:15 PM, nick pitlosh via zfs-discuss wrote:
> >> im guessing this is a vmware box, and pretty busy eh? figure out how to
> >> turn off the ram in the zil. thats all you can do, zfs is constantly
> >> streaming data to disk in that situation, and while all of it is sync,
> >> the zil is ram backed.
> >
> > I'm not sure what your point is here, but… they've got a
> > capacitor-backed SLOG set up, and as their client application reports
> > data corruption (even though their SLOG, and pool, is fine) this is not
> > related to RAM in any way.
> >
> > That is, unless they're using non-ECC memory or getting edge case
> > multi-bit errors, which are undedectable by EDAC.
> >
> > I do not think the corruption is related to ZFS, as the pool stays in a
> > consistent state.
> >
> >> why are you losing power?
> >
> > Because they are simulating power-loss scenarios to find out whether
> > their application behaves as intended, see their first post.
> >
> > --
> > Regards,
> > Hajo Möller
> > _______________________________________________
> > zfs-discuss mailing list
> > zfs-discuss at list.zfsonlinux.org
> > http://list.zfsonlinux.org/mailman/listinfo/zfs-discuss
> _______________________________________________
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