On Thu, Apr 21, 2011 at 2:44 PM, Colin McCabe <cmccabe@xxxxxxxxxxxxxx> wrote: > On Thu, Apr 21, 2011 at 2:23 PM, Yehuda Sadeh Weinraub > <yehudasa@xxxxxxxxx> wrote: >> On Thu, Apr 21, 2011 at 2:09 PM, Colin McCabe <cmccabe@xxxxxxxxxxxxxx> wrote: >>> On Thu, Apr 21, 2011 at 1:03 PM, Gregory Farnum >>> <gregory.farnum@xxxxxxxxxxxxx> wrote: >>>> I really don't see how pushing the naming complexity into the local filesystem, >>>> where it adds lots of otherwise-useless inodes and dentries, is going to help us. >>> >>> Here is a quick summary of how the TV's proposal would help us. >>> 1. it avoids collisions entirely >>> 2. You don't ever have do an extra xattr lookup, no matter how short >>> or long the object name is. >> >> Yeah, but you read more directories. Note that btrfs stores the xattrs >> on the directories, so reading those xattrs will have a lower IO >> impact than traversing directories recursively. > > It does seem like btrfs' extended attribute implementation is fairly > efficient. But Linux's dentry cache (dcache) is also pretty efficient. > (resending to list) It needs to be populated first before being efficient. And it'll be less efficient now that you populate it with extra entries. Yehuda -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
