On 2010-11-28, at 14:16, linux_ext4@xxxxxxxxxxxx wrote: > I have a production system installed on an SSD, whose installer formats > the target drive as ext3 automatically. I've since learned that ext4 is > more suited for use on SSDs and am considering an upgrade to ext4. > > I see the procedure on how to convert from ext3 to ext4 on the wiki, and > before I proceed would like to know whether there's an advantage to > formatting as ext4 from the start as opposed to converting after an ext3 > format. It is possible to use the ext4 filesystem code on ext3-formatted filesystems without any conversion being done. Enabling extents will improve performance, and uninit_bg will improve e2fsck performance. You wouldn't be able to take advantage of flex_bg without reformatting (or some significant surgery to resize2fs). If the inodes are "large" (256 bytes) then mounting the filesystem with ext4 will allow the inodes to use nanosecond timestamps. > In the case that there is a difference, what exactly is sacrificed in > choosing one over the other? Reformatting and reinstalling and/or restoring from backup into an ext4-formatted filesystem will allow using a few of the features lay out the files with extents, and reduce the metadata overhead. There will be some performance benefits, but I don't think it will necessarily be dramatic. Cheers, Andreas -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
