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From: Richard Purdie <richard.purdie@linuxfoundation.org>
To: Laurentiu Palcu <laurentiu.palcu@intel.com>
Cc: openembedded-core@lists.openembedded.org
Subject: Re: [PATCH 0/5] Remove /var/cache from volatiles directory
Date: Mon, 04 Feb 2013 11:51:32 +0000	[thread overview]
Message-ID: <1359978692.14071.152.camel@ted> (raw)
In-Reply-To: <510F875B.9070903@intel.com>

On Mon, 2013-02-04 at 12:03 +0200, Laurentiu Palcu wrote:
> 
> On 02/04/2013 11:46 AM, Mike Looijmans wrote:
> > On 02/04/2013 10:26 AM, Laurentiu Palcu wrote:
> >> > Hi,
> >> >
> >> > Re-generating applications' cache every time the system is rebooted is not a
> >> > very efficient process for an embedded device. Usually, the cache directory is
> >> > used by applications to store data resulting from time consmuming I/O or
> >> > calculation. So, this patchset will take out /var/cache from tmpfs.
> > What if you have a READONLY rootfs? This patch will "break" those 
> > devices I think.
> > 
> > 
> 
> Not necessarily. We are trying to have all postinstalls run on host, so
> we don't have to do any postinstall activity on target. Any cache
> generated during postinstall, will be generated at do_rootfs time. Then,
> we can deploy the image with the cache already in place.
> 
> Also, on a RO rootfs, there is really no need to update the cache since
> the cached files do not really change. Hence, the cache created on host
> should, in theory, be valid.
> 
> If the above logic is missing anything, feel free to correct me.

If this is an issue and something does need to touch the cache
directory, we can mount a unionfs over /var/cache like we're doing
for /var/lib in the readonly rootfs patch series.

Ultimately, I think we're better served with that approach all round.

Cheers,

Richard




  reply	other threads:[~2013-02-04 12:07 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-04  9:26 [PATCH 0/5] Remove /var/cache from volatiles directory Laurentiu Palcu
2013-02-04  9:26 ` [PATCH 1/5] base-files: remove /var/cache from volatiles Laurentiu Palcu
2013-02-04  9:26 ` [PATCH 2/5] fs-perms: " Laurentiu Palcu
2013-02-04  9:26 ` [PATCH 3/5] initscripts: " Laurentiu Palcu
2013-02-04  9:26 ` [PATCH 4/5] systemd: " Laurentiu Palcu
2013-02-04  9:26 ` [PATCH 5/5] rpm: remove /var/volatiles/cache/rpm from the FILEs list Laurentiu Palcu
2013-02-04  9:46 ` [PATCH 0/5] Remove /var/cache from volatiles directory Mike Looijmans
2013-02-04 10:03   ` Laurentiu Palcu
2013-02-04 11:51     ` Richard Purdie [this message]
2013-02-04 17:47     ` Phil Blundell
2013-02-04 17:51       ` Burton, Ross
2013-02-04 18:25         ` Enrico Scholz
2013-02-04 19:36           ` Burton, Ross
2013-02-05  2:37 ` ChenQi
2013-02-05  9:56   ` Laurentiu Palcu
2013-02-05 20:50 ` Saul Wold

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