Tim wrote: > On Mon, Jan 19, 2009 at 1:12 PM, Bob Friesenhahn > <bfrie...@simple.dallas.tx.us <mailto:bfrie...@simple.dallas.tx.us>> wrote: > > On Mon, 19 Jan 2009, Adam Leventhal wrote: > > > Are you telling me zfs is deficient to the point it can't > handle basic > right-sizing like a 15$ sata raid adapter? > > > How do there $15 sata raid adapters solve the problem? The more > details you > could provide the better obviously.
Note that for the LSI RAID controllers Sun uses on many products, if you take a disk that was JBOD and tell the controller to make it RAIDed, then the controller will relabel the disk for you and will cause you to lose the data. As best I can tell, ZFS is better in that it will protect your data rather than just relabeling and clobbering your data. AFAIK, NVidia and others do likewise. > It is really quite simple. If the disk is resilvered but the new > drive is a bit too small, then the RAID card might tell you that a > bit of data might have lost in the last sectors, or it may just > assume that you didn't need that data, or maybe a bit of cryptic > message text scrolls off the screen a split second after it has been > issued. Or if you try to write at the end of the volume and one of > the replacement drives is a bit too short, then the RAID card may > return a hard read or write error. Most filesystems won't try to > use that last bit of space anyway since they run real slow when the > disk is completely full, or their flimsy formatting algorithm always > wastes a bit of the end of the disk. Only ZFS is rash enough to use > all of the space provided to it, and actually expect that the space > continues to be usable. > > > > It's a horribly *bad thing* to not use the entire disk and right-size it > for sanity's sake. That's why Sun currently sells arrays that do JUST > THAT. ?? > I'd wager fishworks does just that as well. Why don't you open source > that code and prove me wrong ;) I don't think so, because fishworks is an engineering team and I don't think I can reserve space on a person... at least not legally where I live :-) But this is not a problem for the Sun Storage 7000 systems because the supported disks are already "right-sized." > I'm wondering why they don't come right out with it and say "we want to > intentionally make this painful to our end users so that they buy our > packaged products". It'd be far more honest and productive than this > pissing match. I think that if there is enough real desire for this feature, then someone would file an RFE on http://bugs.opensolaris.org It would help to attach diffs to the bug and it would help to reach a concensus of the amount of space to be reserved prior to filing. This is not an intractable problem and easy workarounds already exist, but if ease of use is more valuable than squeezing every last block, then the RFE should fly. -- richard _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
