GNU bug report logs - #29675
databases should be created with chattr +C

Previous Next

To add a comment to this bug, you must first unarchive it, by sending
a message to control AT debbugs.gnu.org, with unarchive 29675 in the body.
You can then email your comments to 29675 AT debbugs.gnu.org in the normal way.

Toggle the display of automated, internal messages from the tracker.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Efraim Flashner <efraim <at> flashner.co.il>
To: bug-guix <at> gnu.org
Subject: databases should be created with chattr +C
Date: Tue, 12 Dec 2017 13:46:08 +0200

[Message part 1 (text/plain, inline)]

We support running GuixSD on top of btrfs, and the prevailing wisdom is
to mark databases (sqlite, postgresql, etc.) as 'chattr +C', that is, as
not copy-on-write. It is honored under ext4, but it shouldn't cause any
changes.

-- 
Efraim Flashner   <efraim <at> flashner.co.il>   אפרים פלשנר
GPG key = A28B F40C 3E55 1372 662D  14F7 41AA E7DC CA3D 8351
Confidentiality cannot be guaranteed on emails sent or received unencrypted

[signature.asc (application/pgp-signature, inline)]

Message #8 received at 29675 <at> debbugs.gnu.org (full text, mbox):

From: Rutger Helling <rhelling <at> mykolab.com>
To: 29675 <at> debbugs.gnu.org
Cc: efraim <at> flashner.co.il
Subject: Re: bug#29675: databases should be created with chattr +C
Date: Wed, 13 Dec 2017 09:50:55 +0100

This should also be done with virtual machine images.

Message #11 received at 29675 <at> debbugs.gnu.org (full text, mbox):

From: Danny Milosavljevic <dannym <at> scratchpost.org>
To: Efraim Flashner <efraim <at> flashner.co.il>
Cc: 29675 <at> debbugs.gnu.org
Subject: Re: bug#29675: databases should be created with chattr +C
Date: Wed, 13 Dec 2017 15:40:03 +0100

Hi Efraim,

On Tue, 12 Dec 2017 13:46:08 +0200
Efraim Flashner <efraim <at> flashner.co.il> wrote:

> We support running GuixSD on top of btrfs, and the prevailing wisdom is
> to mark databases (sqlite, postgresql, etc.) as 'chattr +C', that is, as
> not copy-on-write. It is honored under ext4, but it shouldn't cause any
> changes.

It sounds reasonable to do that - but I don't think that relational databases are managed by the Guix store.  Rather they are in /var or in the home directory.  Long story short, it would make sense for Postgres and Sqlite upstream to do the chattr +C, if they don't already do it.

Message #14 received at 29675 <at> debbugs.gnu.org (full text, mbox):

From: ludo <at> gnu.org (Ludovic Courtès)
To: Danny Milosavljevic <dannym <at> scratchpost.org>
Cc: 29675 <at> debbugs.gnu.org, Efraim Flashner <efraim <at> flashner.co.il>
Subject: Re: bug#29675: databases should be created with chattr +C
Date: Wed, 20 Dec 2017 14:12:39 +0100

Hello,

Danny Milosavljevic <dannym <at> scratchpost.org> skribis:

> On Tue, 12 Dec 2017 13:46:08 +0200
> Efraim Flashner <efraim <at> flashner.co.il> wrote:
>
>> We support running GuixSD on top of btrfs, and the prevailing wisdom is
>> to mark databases (sqlite, postgresql, etc.) as 'chattr +C', that is, as
>> not copy-on-write. It is honored under ext4, but it shouldn't cause any
>> changes.
>
> It sounds reasonable to do that - but I don't think that relational databases are managed by the Guix store.  Rather they are in /var or in the home directory.  Long story short, it would make sense for Postgres and Sqlite upstream to do the chattr +C, if they don't already do it.

I agree.

Efraim, unless we have a specific example, I’m inclined to close it as
“not-a-bug”, with the understanding that it’s an upstream issue rather
than something GuixSD-specific.

How does that sound?

Ludo’.

Message #17 received at 29675 <at> debbugs.gnu.org (full text, mbox):

From: Efraim Flashner <efraim <at> flashner.co.il>
To: Ludovic Courtès <ludo <at> gnu.org>
Cc: 29675 <at> debbugs.gnu.org, Danny Milosavljevic <dannym <at> scratchpost.org>
Subject: Re: bug#29675: databases should be created with chattr +C
Date: Wed, 20 Dec 2017 15:31:12 +0200

[Message part 1 (text/plain, inline)]

On Wed, Dec 20, 2017 at 02:12:39PM +0100, Ludovic Courtès wrote:
> Hello,
> 
> Danny Milosavljevic <dannym <at> scratchpost.org> skribis:
> 
> > On Tue, 12 Dec 2017 13:46:08 +0200
> > Efraim Flashner <efraim <at> flashner.co.il> wrote:
> >
> >> We support running GuixSD on top of btrfs, and the prevailing wisdom is
> >> to mark databases (sqlite, postgresql, etc.) as 'chattr +C', that is, as
> >> not copy-on-write. It is honored under ext4, but it shouldn't cause any
> >> changes.
> >
> > It sounds reasonable to do that - but I don't think that relational databases are managed by the Guix store.  Rather they are in /var or in the home directory.  Long story short, it would make sense for Postgres and Sqlite upstream to do the chattr +C, if they don't already do it.
> 
> I agree.
> 
> Efraim, unless we have a specific example, I’m inclined to close it as
> “not-a-bug”, with the understanding that it’s an upstream issue rather
> than something GuixSD-specific.
> 
> How does that sound?
> 
> Ludo’.

My intention was that after creating the database in /var that it should
get 'chattr +C file', but it actually looks like people are divided
between less fragmentation from not CoW for the database or more
recovery options from having it CoW and the checksumming, so closing it
and leaving it alone for now seems best.

-- 
Efraim Flashner   <efraim <at> flashner.co.il>   אפרים פלשנר
GPG key = A28B F40C 3E55 1372 662D  14F7 41AA E7DC CA3D 8351
Confidentiality cannot be guaranteed on emails sent or received unencrypted

[signature.asc (application/pgp-signature, inline)]

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.