I am creating a fresh install for Zimbra 7.x on Ubuntu 10.04.

When ext4 first became common there were concerns in some circles regarding greater data-loss risk in some circumstances (like a power-out) due to changes in default sync behaviours and such, so many recommended staying with ext3 for the time being and some tools (VirtualBox for instance) still give warnings when you use them on an ext4 filesystem.

It there any official recommendation for Zimbra on Ubuntu 10.04 running in a VM? Accept the default ext4 for the performance benefits it promises, or select ext3 as it may be considered safer?