zfs discuss - Dec 2008 - Changing casesensitivity for existing filesystems?

I tried this question in the CIFS forum and didn''t get any responses,
but maybe it is more appropriate for this forum.

I have many large zfs filesystems on Solaris 10 servers that I would like to
upgrade to OpenSolaris so the filesystems can be shared using the CIFS Service
(I''m currently using Samba). ZFS on the Solaris 10 installations
don''t have some of the newer features such as the casesensitivity
option.

I would like to set casesensitivity to mixed, but I can''t see any way
to do it without creating new filesystems and copying the data. Considering the
amount of data and all the supporting snapshots this could become a major task.

Any ideas or shortcuts to accomplish this would be very welcome.

Thank you.
-- 
This message posted from opensolaris.org

On Wed, Dec 10, 2008 at 10:51 AM, Jay Anderson <Jay.Anderson00 at
gmail.com>wrote:
> I tried this question in the CIFS forum and didn''t get any
responses, but
> maybe it is more appropriate for this forum.
>
> I have many large zfs filesystems on Solaris 10 servers that I would like
> to upgrade to OpenSolaris so the filesystems can be shared using the CIFS
> Service (I''m currently using Samba). ZFS on the Solaris 10
installations
> don''t have some of the newer features such as the casesensitivity
option.
>
> I would like to set casesensitivity to mixed, but I can''t see any
way to do
> it without creating new filesystems and copying the data. Considering the
> amount of data and all the supporting snapshots this could become a major
> task.
>
> Any ideas or shortcuts to accomplish this would be very welcome.
>
> Thank you.
> --
>
Why can''t you just upgrade zfs and change the pool setting?  Why would
you
need to copy the data?

--Tim
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On Wed, Dec 10, 2008 at 11:40:16AM -0600, Tim wrote:
> On Wed, Dec 10, 2008 at 10:51 AM, Jay Anderson <Jay.Anderson00 at
gmail.com>wrote:
> > I have many large zfs filesystems on Solaris 10 servers that I would
like
> > to upgrade to OpenSolaris so the filesystems can be shared using the
CIFS
> > Service (I''m currently using Samba). ZFS on the Solaris 10
installations
> > don''t have some of the newer features such as the
casesensitivity option.
The casesensitivity ZFS dataset property, and everything else that''s
associated with the Solaris SMB server, will NOT be backported to S10.
That doesn''t mean you have to migrate your data though; see below.
> > I would like to set casesensitivity to mixed, but I can''t see
any way to do
> > it without creating new filesystems and copying the data. Considering
the
> > amount of data and all the supporting snapshots this could become a
major
> > task.
You don''t have to copy any data, just install OpenSolaris, upgrade your
pools and set casesensitivity to your liking.  Do note that some
properties, like utf8only and normalization cannot be changed after a
dataset is created.
> Why can''t you just upgrade zfs and change the pool setting?  Why
would you
> need to copy the data?
Right, but keep in mind that Jay will have to move to OpenSolaris to get
the casesensitivity property.

Nico
--

On Wed, Dec 10, 2008 at 11:46 AM, Nico wrote:
> On Wed, Dec 10, 2008 at 10:51 AM, Jay Anderson wrote:
> > I have many large zfs filesystems on Solaris 10 servers that I would
like
> > to upgrade to OpenSolaris so the filesystems can be shared using the
CIFS
> > Service (I''m currently using Samba). ZFS on the Solaris 10
installations
> > don''t have some of the newer features such as the
casesensitivity option.
>
> The casesensitivity ZFS dataset property, and everything else
that''s
> associated with the Solaris SMB server, will NOT be backported to S10.
> That doesn''t mean you have to migrate your data though; see below.
Yep, that''s why I''m planning to upgrade to OpenSolaris.
> > I would like to set casesensitivity to mixed, but I can''t see
any way to do
> > it without creating new filesystems and copying the data. Considering
the
> > amount of data and all the supporting snapshots this could become a
major
> > task.
>
> You don''t have to copy any data, just install OpenSolaris, upgrade
your
> pools and set casesensitivity to your liking. Do note that some
> properties, like utf8only and normalization cannot be changed after a
> dataset is created.
The casesensitivity option is just like utf8only and normalization, it can only
be set at creation time. The result from attempting to change it on an existing
filesystem:

    # zfs set casesensitivity=mixed pool0/data1
    cannot set property for ''pool0/data1'':
''casesensitivity'' is readonly
>From the ZFS Administration Guide
(http://docs.sun.com/app/docs/doc/817-2271/6mhupg6lc?a=view#indexterm-319):
Regardless of the casesensitivity property setting, the file system preserves
the case of the name specified to create a file. This property cannot be changed
after the file system is created.

Thanks for any suggestions to help get around having to migrate the data.
-- 
This message posted from opensolaris.org

On Wed, Dec 10, 2008 at 11:13:21AM -0800, Jay Anderson
wrote:
> The casesensitivity option is just like utf8only and normalization, it
> can only be set at creation time. The result from attempting to change
> it on an existing filesystem:
> 
>     # zfs set casesensitivity=mixed pool0/data1
>     cannot set property for ''pool0/data1'':
''casesensitivity'' is readonly
> 
> >From the ZFS Administration Guide
(http://docs.sun.com/app/docs/doc/817-2271/6mhupg6lc?a=view#indexterm-319):
The manpage I looked at didn''t mention that, though it did for
normalization and utf8only, so I foolishly stopped there.  Sounds like a
manpage bug.  My apologies for the confusion.

I would think only the casesensitivity=mixed should have to be set at
creation time, that casesensitivity=insensitive could be set at any
time.  Hmmm.

Nico
--

On Wed, 10 Dec 2008 11:13:21 PST
Jay Anderson <Jay.Anderson00 at gmail.com> wrote:
> Yep, that''s why I''m planning to upgrade to OpenSolaris.
And do you think it really is stable/secure enough for a production
server replacing S10?

-- 
Dick Hoogendijk -- PGP/GnuPG key: 01D2433D
+ http://nagual.nl/ | SunOS sxce snv103 ++
+ All that''s really worth doing is what we do for others (Lewis Carrol)

Nicolas Williams wrote:
> On Wed, Dec 10, 2008 at 11:13:21AM -0800, Jay Anderson wrote:
>> The casesensitivity option is just like utf8only and normalization, it
>> can only be set at creation time. The result from attempting to change
>> it on an existing filesystem:
>>
>>     # zfs set casesensitivity=mixed pool0/data1
>>     cannot set property for ''pool0/data1'':
''casesensitivity'' is readonly
>>
>> >From the ZFS Administration Guide
(http://docs.sun.com/app/docs/doc/817-2271/6mhupg6lc?a=view#indexterm-319):
> 
> The manpage I looked at didn''t mention that, though it did for
> normalization and utf8only, so I foolishly stopped there.  Sounds like a
> manpage bug.  My apologies for the confusion.
> 
The manpage reads:

      The following three properties cannot be changed  after  the
      file  system  is  created, and therefore, should be set when
      the file system is created. If the properties  are  not  set
      with the "zfs create" or "zpool create" commands,
these pro-
      perties are inherited from the parent dataset. If the parent
      dataset  lacks  these  properties due to having been created
      prior to these features being supported, the new file system
      will have the default values for these properties.

      casesensitivity = sensitive | insensitive | mixed

	...

      normalization =none | formD | formKCf

	...

      utf8only =on | off

	...

We reiterate that the property cannot be changed in the paragraphs 
describing the second two, perhaps we should do so for the first as well.
> I would think only the casesensitivity=mixed should have to be set at
> creation time, that casesensitivity=insensitive could be set at any
> time.  Hmmm.
> 
We don''t allow this for a couple of reasons.  If the file system was 
case-sensitive or mixed and you suddenly make it insensitive, you 
potentially create name conflicts:

% ls
Readme README readme

if we make this case-insensitive all of sudden you''ve got two files
that
can no longer be looked up.

The other reason is performance.  Knowing beforehand that we need to 
track or disallow case conflicts helps us to optimize to keep lookups fast.

-tim
> Nico

> > I would think only the casesensitivity=mixed should have to be set at
> > creation time, that casesensitivity=insensitive could be set at any
> > time.  Hmmm.
> > 
> 
> We don''t allow this for a couple of reasons.  If the file system
was
> case-sensitive or mixed and you suddenly make it insensitive, you 
> potentially create name conflicts:
> 
> % ls
> Readme README readme
> 
> if we make this case-insensitive all of sudden you''ve got two
files that
> can no longer be looked up.
> 
> The other reason is performance.  Knowing beforehand that we need to 
> track or disallow case conflicts helps us to optimize to keep lookups fast.
> 
> -tim
> 
Thank you for the clarification, and the explanation. I can see there are
serious problems with ever being able to go from case-sensitive or mixed to
case-insensitive. However, to aid with migration from existing ZFS filesystems
that don''t have the casesensitivity option to newer ZFS versions with
the option it would be very helpful to have some kind of an optimization routine
to allow changing from case-insensitive to mixed. This would make it much easier
to transition from Samba to CIFS Server.

I would much prefer to wait several hours for an optimization routine to run in
converting from case-sensitive to mixed on a newly imported filesystem than to
have to migrate the data to a new filesystem.

Thank you.
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