On Wed, Oct 05, 2011 at 09:58:59AM -0500, Eric Sandeen wrote:
right; for large ext4 fs use (or testing), try
# mkfs.ext4 -E lazy_itable_init=1 /dev/blah
this will cause it to skip inode table initialization, and speed up mkfs a LOT. It'll also keep sparse test images smaller.
IMHO this should probably be made default above a certain size.
You almost preempted my question: Could I use this for every ext4 filesystem I make? Honestly from a virt / libguestfs p.o.v. it sounds like something we should always do.
The tradeoff is that inode table initialization happens in kernelspace, post-mount - with efforts made to do it in the background, and not impact other I/O too much.
Is there a circumstance where this is bad? I'm thinking perhaps a case where you create a filesystem and immediately try to populate it with lots of files.
Rich.