> So, is there a > sleep/hibernation/standby mode that the hot spares > operate in or are they on all the time regardless of > whether they are in use or not?
This depends on the power-save options of your hardware, not on ZFS. Arguably, there is less ware on the heads for a hot spare. I guess that many modern disks will park the heads after a certain time, or spin even down, unless the controller prevents that. The question is if the disk comes back fast enough when required - your bets are on the controller supporting that properly. As it seems, there is little focus on that matter at SUN and among community members. At least my own investigations how to best make use of power save options like most SoHo NAS boxes offer returned only dire results. > Usually the hot spare is on a not so well-performing > SAS/SATA controller, There is no room for "not so well-performing" controllers in my servers. I would not allow wasting PCIe slots, backplanes for anything that doesn't live up to specs (my requirements). That being said, JBOD HBAs are those that perform best with ZFS and those happen to be not very expensive. Additionally, I will avoid a checker-board of components striving for keeping things as simple as possible. > To be more general; are the hard drives in the pool > "hard coded" to their SAS/SATA channels or can I swap > their connections arbitrarily if I would want to do > that? Will zfs automatically identify the association > of each drive of a given pool or tank and > automatically reallocate them to put the > pool/tank/filesystem back in place? This works very well, given your controller properly supports it. I tried that on an Areca 1170 a couple of weeks ago, with interesting results that turned out to be an Areca firmware flaw. You may find the thread on this list. I would recommend that you do such tests when implementing your array before going in production with it. Analogue aspects may apply for - Hotswapping - S.M.A.R.T. - replace failing components or change configuration - transfer a whole array to another host (list is not comprehensive) I think at this moment you have two choices to be sure that all "advertised" ZFS features will be available in your system: - learning it the hard way by try and error - use SUN hardware, or another turnkey solution that offers ZFS, such as NexentaStore A popular approach is following along the rails of what is being used by SUN, a prominent example being the LSI 106x SAS HBAs in "IT" mode. Regards, Tonmaus -- This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
