>>>>> "Chris" == Chris Mason <chris.mason@xxxxxxxxxx> writes: Chris> On Wed, Jun 13, 2007 at 10:00:56AM -0400, John Stoffel wrote: >> >>>>> "Chris" == Chris Mason <chris.mason@xxxxxxxxxx> writes: >> >> As a user of Netapps, having quotas (if only for reporting purposes) >> >> and some way to migrate non-used files to slower/cheaper storage would >> >> be great. >> Chris> So far, I'm not planning quotas beyond the subvolume level. >> >> So let me get this straight. Are you saying that quotas would only be >> on the volume level, and for the initial level of sub-volumes below >> that level? Or would *all* sub-volumes have quota support? And does >> that include snapshots as well? Chris> On disk, snapshots and subvolumes are identical...the only Chris> difference is their starting state (sorry, it's confusing, and Chris> it doesn't help that I interchange the terms when describing Chris> features). Ok, that's fine. A sub-volume is the unit and depending on it's state, it's either a snapshot of an existing volume, or it's a volume on it's own, though it still has a parent (?) which it is mounted below? Do I have it right now? Chris> Every subvolume will have a quota on the number of blocks it Chris> can consume. I haven't yet decided on the best way to account Chris> for blocks that are actually shared between snapshots, but Chris> it'll be in there somehow. So if you wanted to make a snapshot Chris> readonly, you just set the quota to 1 block. Ok, so you really aren't talking about Quotas here, but space reservations instead. Also, I think you're wrong here when you state that making a snapshot (sub-volume?) RO just requires you to set the quota to 1 block. What is to stop me from writing 1 block to a random file that already exists? Chris> But, I'm not planning on adding a way to say user X in Chris> subvolume Y has quota Z. I'll just be: this subvolume can't Chris> get bigger than a given size. (at least for version 1.0). Ok, so version 1.0 isn't as interesting to me in a production environment, since we pretty much need quotas (or a quick way to monitor how much space a user has been allocated on a volume. But for a home system, it's certainly looking interesting as well, since I could give each home directory it's own sub-volume and just grow/shrink them as needed. Maybe. :] Thanks for your work on this. John - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
