Re: Firefox profiles on a tmpfs (ramdisk)?
The question is, are Ubuntu developers interested in this? No. Understood. Would it be possible to add the Firefox startup and shutdown script hooks into Firefox run-mozilla.sh in Ubuntu, though? Have you tried using libeatmydata? The only key difference there should be with using tmpfs is that it effectively makes fsync() a noop. No, libeatmydata is risky. The profile may be garbled if Firefox crashes. Using a limited size profile and tmpfs (say, 64 MB) I can keep the profile in memory even in low memory situations, without risking the profile integrity. The profile is saved in exactly the state Firefox leaves it when it closes or crashes. If the workstation crashes, with tmpfs the changes made in the current session are lost, and the profile reverts to the previous state. Some users might prefer this behaviour; I do. Using tmpfs, I can save and snapshot the active profile at any time, for example in suspend scripts. As long as Firefox syncs changesets to the profile files properly, the profile can be copied at any time. With a helper, one could save the profile periodically, e.g. after suitable periods of inactivity. Thanks anyway, Jouko -- Ubuntu-devel-discuss mailing list Ubuntu-devel-discuss@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel-discuss
Re: Firefox profiles on a tmpfs (ramdisk)?
On 10/25/2010 1:34 PM, Jouko Orava wrote: Using tmpfs, I can save and snapshot the active profile at any time, for example in suspend scripts. As long as Firefox syncs changesets to the profile files properly, the profile can be copied at any time. With a helper, one could save the profile periodically, e.g. after suitable periods of inactivity. This is not true. If you copy the file wile ff is changing it, you can end up with a corrupt copy. -- Ubuntu-devel-discuss mailing list Ubuntu-devel-discuss@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel-discuss
Re: Firefox profiles on a tmpfs (ramdisk)?
Using tmpfs, I can save and snapshot the active profile at any time, This is not true. If you copy the file wile ff is changing it, you can end up with a corrupt copy. I meant that you can get a copy of the profile state as if Firefox had crashed at that point. (You can take a snapshot opportunistically at any time, by first taking the snapshot of the profile, and then checking that the files were not modified in the last two seconds, and will not be modified in the next two seconds. If the profile is on tmpfs, writes should affect metadata immediately, and the two-second limit takes care of any clock granularity issues. If the user is active and the files were modified in the grace period, the snapshot may be broken, just as if Firefox had crashed.) Since Firefox is supposed to be able to recover the session from a crash, you *should* be able to take a snapshot of the active profile at any time. In fact, if you monitor Firefox file access patterns with e.g. inotifywait -m -r path-to-the-active-profile-directory or by stracing firefox-bin, you can see that both the session store (sessionstore.js) and the places database (places.sqlite*) are modified in a way that makes snapshotting safe. (sessionstore.js is written to a temporary file, synced, then the original replaced with the temporary copy; places has a separate journal file which is written and synced before data is written to the db.) Cheers, Jouko -- Ubuntu-devel-discuss mailing list Ubuntu-devel-discuss@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel-discuss
Re: Firefox profiles on a tmpfs (ramdisk)?
On 10/24/2010 10:12 AM, Jouko Orava wrote: Hello, For a couple of years now I've kept my active Firefox profiles on a tmpfs (mounted size=128M,mode=01777,atime,auto,rw,nodev,noexec,nosuid) on both my desktop workstation and on my minilaptop. It feels subjectively much snappier, but I haven't actually measured the difference. On the laptop, it also reduces disk usage, which is very nice. The profiles are unpacked from a tarball when firefox starts, and tarred back when firefox closes, using two script hooks in run-mozilla.sh: [ -x /usr/lib/firefox-profiles.sh ] /usr/lib/firefox-profiles.sh load just before the final if clause, and [ -x /usr/lib/firefox-profiles.sh ] /usr/lib/firefox-profiles.sh save just after the final if clause. The script itself is very careful to not fail (and not to overwrite the old tarball unless the new one is ok), and has never failed yet, even when Firefox crashes. I tried to get something similar upstream earlier: https://bugzilla.mozilla.org/show_bug.cgi?id=576707 but it was rejected for complexity reasons. If the Ubuntu Mozilla team were to add the script hook into Firefox -- noting that it does not change the behaviour by default, only if the hooked script actually exists --, I could create an Ubuntu package, which when installed creates the necessary tmpfs, profile tarballs, and modifications to the profile configs to limit the profile size (so that the tmpfs does not grow too large). All of the changes are also safely undoable if the package is removed. Each user can also choose which profiles, if any, are kept on the tmpfs. The question is, are Ubuntu developers interested in this? It does add changes to Firefox run-mozilla.sh script, which has to be maintained. (However, run-mozilla.sh does not seem to change often.) If there is interest for this, I could upload or e-mail the scripts (/usr/lib/firefox-profiles.sh for Firefox, and proposed maintainer scripts for a package setting up the tmpfs and moving Firefox profiles to a tmpfs.) (There are also some user interface related issues to think about, too. For example, should the package move all profiles to tmpfs by default, or should it have a GUI prompting the user on the next Firefox startup? Is there need for a migration tool, GUI or commandline, so that users could choose afterwards?) At the minimum, adding the script hook into run-mozilla.sh makes the testing much easier. Now, I need to modify run-mozilla.sh whenever Firefox is updated, which is a bit of a chore.. I'd be very happy to provide further information for those interested. Cheers, Jouko Orava If upstream rejected for complexity, we won't be able to take it either. We will be discussing increasing the time between session saves in Firefox though. Thanks, Micah Gersten Ubuntu Mozilla Team -- Ubuntu-devel-discuss mailing list Ubuntu-devel-discuss@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel-discuss
