Hi,
hw wrote:
> with CDs/DVDs, writing is not so easy.
Thus it is not as easy to overwrite them by mistake.
The complicated part of optical burning can be put into scripts.
But i agree that modern HDD sizes cannot be easily covered by optical
media.
I wrote:
> > [...] LTO tapes [...]
hw
On Thu, 2022-11-10 at 15:32 +0100, Thomas Schmitt wrote:
> Hi,
>
> i wrote:
> > > the time window in which the backuped data
> > > can become inconsistent on the application level.
>
> hw wrote:
> > Or are you referring to the data being altered while a backup is in
> > progress?
>
> Yes.
Ah I
On Sat, Nov 12, 2022 at 01:39:56PM -0500, Stefan Monnier wrote:
But as I mentioned, higher-layers (the filesystem layer, and the
applications running on top of that) *should* try and make sure that
a hard failure (kernel crash, power failure, ... these and up taking
a snapshot of your block
> It took me a while to find out how the block layer can ensure that a
> snapshot is consistent on the filesystem level. The answer is Linux VFS
> method super_operations.freeze_fs().
> https://www.kernel.org/doc/html/latest/filesystems/vfs.html
> Without it a snapshot on block level would be
Hi,
Stefan Monnier wrote:
> Presumably the "backuper" is the sysadmin, i.e. the same (group of)
> person who chose the filesystem, so I'd say yes the "backuper" is
> to blame.
I rather mean the whole complex of system maintainer, users, and
backup software.
But even if there is a qualified
>> Arguably this can be considered as a bug in the application (because
>> a failure in the middle could thus result in an inconsistent state).
> A backup programmer or operator does not necessarily have influence on
> such applications.
Indeed it remains a real problem, that can be solved only
Hi,
i wrote:
> > Data of different files or at different places in the same file
> > may have relations which may become inconsistent during change operations
> > until the overall change is complete.
Stefan Monnier wrote:
> Arguably this can be considered as a bug in the application (because
>
>> Or are you referring to the data being altered while a backup is in
>> progress?
> Yes. Data of different files or at different places in the same file
> may have relations which may become inconsistent during change operations
> until the overall change is complete.
Arguably this can be
Hi,
i wrote:
> > the time window in which the backuped data
> > can become inconsistent on the application level.
hw wrote:
> Or are you referring to the data being altered while a backup is in
> progress?
Yes. Data of different files or at different places in the same file
may have relations
On Wed, 2022-11-09 at 12:08 +0100, Thomas Schmitt wrote:
> Hi,
>
> i wrote:
> > > https://github.com/dm-vdo/kvdo/issues/18
>
> hw wrote:
> > So the VDO ppl say 4kB is a good block size
>
> They actually say that it's the only size which they support.
>
>
> > Deduplication doesn't work when
On 11/9/22 03:08, Thomas Schmitt wrote:
So i would use at least four independent storage facilities interchangeably.
I would make snapshots, if the filesystem supports them, and backup those
instead of the changeable filesystem.
I would try to reduce the activity of applications on the
On Wed, 2022-11-09 at 14:44 +0100, didier gaumet wrote:
> Le 09/11/2022 à 14:25, hw a écrit :
>
> > I don't think it was, see https://docs.freebsd.org/en/books/handbook/zfs/
> >
> > I does mention performance, but I remember other statements saying that was
> > designed for arrays with 40+ disks
Le 09/11/2022 à 14:25, hw a écrit :
I don't think it was, see https://docs.freebsd.org/en/books/handbook/zfs/
I does mention performance, but I remember other statements saying that was
designed for arrays with 40+ disks and, besides data integrity, with ease of use
in mind. Performance
On Wed, 2022-11-09 at 11:05 +0100, didier gaumet wrote:
> Le 09/11/2022 à 10:27, hw a écrit :
> [...]
> > Yes, I've seen those. I can only wonder how much performance impact VDO
> > would
> > have for backups. And I wonder why it doesn't require as much memory as ZFS
> > seems to need for
Hi,
i wrote:
> > https://github.com/dm-vdo/kvdo/issues/18
hw wrote:
> So the VDO ppl say 4kB is a good block size
They actually say that it's the only size which they support.
> Deduplication doesn't work when files aren't sufficiently identical,
The definition of sufficiently identical
On Tue, 2022-11-08 at 11:11 +0100, Thomas Schmitt wrote:
> Hi,
>
> hw wrote:
> > I still wonder how VDO actually works.
>
> There is a comparer/decider named UDS which holds an index of the valid
> storage blocks, and a device driver named VDO which performes the
> deduplication and hides its
Le 09/11/2022 à 10:27, hw a écrit :
[...]
Yes, I've seen those. I can only wonder how much performance impact VDO would
have for backups. And I wonder why it doesn't require as much memory as ZFS
seems to need for deduplication.
It's *only* an hypothesis, but I would suppose that ZFS was
On Tue, 2022-11-08 at 10:04 +0100, didier gaumet wrote:
> Le 08/11/2022 à 05:13, hw a écrit :
> > On Mon, 2022-11-07 at 13:57 -0500, rhkra...@gmail.com wrote:
> > >
> > >
> > > I didn't (and don't) know much about deduplication (beyond what you might
> > > deduce from the name), so I google and
Hi,
hw wrote:
> I still wonder how VDO actually works.
There is a comparer/decider named UDS which holds an index of the valid
storage blocks, and a device driver named VDO which performes the
deduplication and hides its internals from the user by providing a
block device on top of the real
Le 08/11/2022 à 05:13, hw a écrit :
On Mon, 2022-11-07 at 13:57 -0500, rhkra...@gmail.com wrote:
I didn't (and don't) know much about deduplication (beyond what you might
deduce from the name), so I google and found this article which was helpful to
me:
*
On Mon, 2022-11-07 at 13:57 -0500, rhkra...@gmail.com wrote:
>
>
> I didn't (and don't) know much about deduplication (beyond what you might
> deduce from the name), so I google and found this article which was helpful to
> me:
>
> *
> didier gaumet wrote:
> > I may be mistaken, but I think there is a confusion here about a
> > deduplication at filesystem level and at backup tool level.
I didn't (and don't) know much about deduplication (beyond what you might
deduce from the name), so I google and found this article which
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