CASC Conversion in 6.0.2

As previously announced, the Warlords of Draenor 6.0.2 pre-patch marks our transition to the new “Content Addressable Storage Container” (CASC) file format system. This transition is an automatic process that will occur through the Battle.net desktop app as it installs Patch 6.0.2. While it shouldn’t require any action on your part, we have a few notes on the process that can help ensure a smooth install.

• By default your Battle.net desktop app is set to download future patch data automatically. If you’ve turned yours off we recommend re-enabling it to download the 6.0.2 patch data. It’s a pretty big patch, and starting now will save you precious Iron Horde-killing time on Tuesday. Your background download settings are configurable per-game, and you can also adjust things like download speed, among other settings.

• There will be one small final patch on 6.0.2 release-day that will include the last few files to install the patch. Right now we’re expecting it to be around 100MB.

• If you’re one to leave your computer on and Battle.net desktop app running, on the morning of the patch release the install and conversion to CASC will happen automatically.

• Hard drive fragmentation can slow down just about anything you do on your computer, but especially when a program needs to move around large data files, like this patch and conversion process will need to. If you haven’t defragged your hard drive in a while, we recommend looking into it as a possible install-time saving preparation step. Note that defrags aren't typically necessary or recommended if using an SSD.

• If you’re coming back to the game and looking to reinstall from scratch, be aware that all game discs out in the world are printed using the old MPQ file format. That means that if you attempt to install from those discs after 6.0.2, the Battle.net desktop app will instead install by downloading the game. That’s of course not necessarily a bad thing, especially because downloading can actually sometimes be faster than a disc install. Discs being printed for Warlords of Draenor, and for future “Battle Chests”, will be printed in the CASC format and they’ll be able to be used to install from as before.

• If you encounter any problems with the install or conversion please visit our Technical Support forum. For additional troubleshooting instructions or to speak with Blizzard support please use the Battle.net Support site.

While we've tried to ensure as speedy a conversion as possible by using most of your existing game data, this is a complex process, and depending on your hardware, hard drive fragmentation and free space, among other factors, this still may take a bit of time to complete. We hope some of these hints help cut that down even further.

10/10/2014 12:53 PMPosted by Fairadey

10/10/2014 12:46 PMPosted by Treeage

Curious about CASC - can we expect the total HD space used by WoW to go down as a result of this new file format, or will it stay about the same?

Apparently it's not removing the old files, so you're going to use more space.

Not entirely accurate. As the conversion processes each MPQ, it deletes it. At the end of the conversion you should be at or around the same folder size if you've already downloaded all of the 6.0.2 data to this point, and should only need around 4GB free for the conversion itself.

Something people have noted in testing though is a lack of "garbage collection", which would cleanup redundant files after new versions are installed. This is an issue mainly in a beta environment as constant (sometimes daily) updates are released and redundant data builds up very quickly, but it isn't something that will immediately result in a larger install upon release of 6.0.2. Implementing garbage collection is something our engineers are working toward.

Hey Bashiok! (Or anyone with a more equipped knowledge on this subject than I),
Just from reading it, does this mean that patching will be easier and more frequent, small tuning updates will be easier and therefore happen more frequently?

The new format allows us a lot of options for how data is delivered and used. I'd recommend reading the original announcement for some of what it already allows us, as well as some ideas we have for the future.