On 10/5/18 5:51 PM, Chris.Moore@xxxxxxxxxxxxx wrote: > Thanks Hannes, > > After some pointers from Shane Seymour I found that the FC and SRP transport layers > have a devloss timer, so that when a device disappears they hold on to the target > information for a time waiting to see if it comes back. The SAS transport layer > doesn't have that feature. > > The options for me then would be to modify scsi_transport_sas.c to implement > the devloss timeout, or to put that functionality into my LLDD. > > I'm willing to put the work into the SAS transport and libsas, but I suspect there's > not a universal need for it. And since my LLDD is for internal use at our company and > won't be upstreamed, I'll probably just do the work there. If anyone feels that this > is a feature that more people would want then I'll look into doing that. > Well ... there has always been some need to have a dev_loss_tmo handler for SAS, too, as the same issues from FC (which led to the implementation of the dev_loss_tmo mechanism) apply for SAS, too. It's just that path failures on SAS occur far less often, so people haven't really noticed. (Correction: they have, but those experience the issues have enough people to throw at the issue :-) And we've already discussed if it possible to have a generic dev_loss mechanism, as we'll be needing a similar thing for FC-NVMe, too. So yes, as SAS dev_loss_tmo would be appreciated, and you really would get brownie points if you make this generic for the block layer :-) Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking hare@xxxxxxx +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton HRB 21284 (AG Nürnberg)
